• JS学习大作业-Excel

      1 <!DOCTYPE html>
  2 <html>
  3 <head>
  4     <meta charset="utf-8" />
  5     <title>"Excel"</title>
  6     <style type="text/css">
  7         img{
  8             pointer-events: none;
  9         }
 10         #maintable {
 11             table-layout: fixed;
 12             border: #999999 1px solid;
 13             border-collapse: collapse;
 14             user-select: none;
 15         }
 16         #maintable td, #maintable th {
 17             box-sizing: border-box;
 18             user-select: none;
 19             height: 20px;
 20              65px;
 21         }
 22         #maintable td {
 23             border: #D4D4D4 1px solid;
 24         }
 25         #maintable th {
 26             border: #999999 1px solid;
 27             background-color: #E6E6E6;
 28             font-size: 13px;
 29             overflow: hidden;
 30         }
 31         #maintable .rowth {
 32              25px;
 33         }
 34         #maintable .colth {
 35             height: 30px;
 36         }
 37         .show {
 38             display: block;
 39         }
 40         .hide {
 41             display: none;
 42         }
 43         #contextmenu {
 44             position: fixed;
 45              120px;
 46             border: #D4D4D4 1px solid;
 47             background-color: white;
 48         }   
 49             #contextmenu div {
 50                 color: #333333;
 51                 padding: 5px 20px;
 52                  120px;
 53                 box-sizing: border-box;
 54                 background-color: white;
 55             }
 56                 #contextmenu div:hover {
 57                     background: #E6E6E6;
 58                 }
 59         #resizeline {
 60             pointer-events: none;
 61             position: absolute;
 62             border-left: dashed 1px red;
 63         }
 64         #selectdiv {
 65             border: green 2px solid;
 66             box-sizing: border-box;
 67             background-color: rgba(200,200,200,0.5);
 68             position: absolute;
 69             pointer-events: none; 
 70         }
 71 
 72     </style>
 73     <script type="text/javascript">
 74         window.addEventListener("load", function () {
 75             new ExcelTable("maintable", 3, 20, 20, 300, 5);
 76         });
 77         function ExcelTable(id, span, initRow, initCol, maxWidthOrHeight, minWidthOrHeight) {
 78             this.span = (undefined == span) ? 3 : span;
 79             this.initRow = initRow;
 80             this.initCol = initCol;
 81             this.maxWidthOrHeight = (undefined == maxWidthOrHeight) ? 300 : maxWidthOrHeight;
 82             this.minWidthOrHeight = (undefined == minWidthOrHeight) ? 5 : minWidthOrHeight;
 83             this.curRow = 0;
 84             this.curCol = 0;// colindex of mouseEvents.target
 85             this.resizeElem = null;// resize operator elem
 86             this.resizeFlag = false;
 87             this.downOffset = 0; //when resize,movedownEvent starting position
 88             this.upOffset = 0; //when resize,moveupEvent ending position
 89             this.selSrcElem = null;//when select,movedownEvent.target
 90             this.selDesElem = null; //when select,moveupEvent.target
 91             this.selFlag = false;    
 92             this.table = document.getElementById(id);
 93             this.allImg=null;
 94             this.resizeLine = null;
 95             this.contextMenu = null;
 96             this.selectDiv = null;
 97             var self = this;
 98             /*this.handler1 = function (e) {
 99                 //var mouseMoveElement = this;//***此时回调的this是触发此事件的元素
100                 self.documentMouseMoveFun(e);
101             };*/
102             this.handler2 = function (e) {
103                 //var mouseMoveElement = this;//***此时回调的this是触发此事件的元素
104                 self.documentMouseUpFun(e);
105             };
106             //other method
107             this.handler1 = (function (me) {
108                 return function (e) {
109                     me.documentMouseMoveFun(e);
110                 };
111             })(this);
112             this.init();
113         }
114         ExcelTable.getOffSet = function (obj) {
115             var p = new Object();
116             p.x = obj.offsetLeft;
117             p.y = obj.offsetTop;
118             obj = obj.offsetParent;
119             while (obj) {
120                 p.x += obj.offsetLeft;
121                 p.y += obj.offsetTop;
122                 obj = obj.offsetParent;
123             }
124             return p;
125         }
126         ExcelTable.calcColNum = function (num) {
127             var colNum = [];
128             var letters = ["A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"];
129             colNum.push(letters[num % letters.length]);
130             num = Math.floor(num / letters.length);
131             while (num) {
132                 --num;
133                 colNum.push(letters[num % letters.length]);
134                 num = Math.floor(num / letters.length);
135             }
136             return colNum.reverse().join("");
137         }
138         ExcelTable.prototype.insertRowOrCol = function () {
139             if (this.curCol == 0) {
140                 this.insertRow();
141             }
142             else if (this.curRow == 0) {
143                 this.insertCol();
144             }
145         }
146         ExcelTable.prototype.insertRow = function () {
147             //real time get latest rowsNum,colsNum
148             var rowsNum = this.table.rows.length;
149             var colsNum = this.table.rows.item(0).cells.length;
150             var row = this.table.insertRow(this.curRow);
151             var th = document.createElement("th");//first insert a th
152             th.className = "rowth";
153             row.appendChild(th);
154             for (var i = 1; i < colsNum; ++i) {
155                 row.insertCell(i);
156             }
157             this.refreshRowSerialNumber();
158         }
159         ExcelTable.prototype.refreshRowSerialNumber = function () {
160             //real time get latest rowsNum,colsNum
161             var rowsNum = this.table.rows.length;
162             for (var j = 1; j < rowsNum; ++j) {
163                 if (j > 0) {
164                     this.table.rows[j].cells[0].innerText = j;
165                 }
166             }
167         }
168         ExcelTable.prototype.insertCol = function () {
169             //real time get latest rowsNum,colsNum
170             var rowsNum = this.table.rows.length;
171             var colsNum = this.table.rows.item(0).cells.length;
172             var th = document.createElement("th");//first insert a th
173             th.className = "colth";
174             this.table.rows[0].insertBefore(th, this.table.rows[0].childNodes[this.curCol]);
175             for (var i = 1; i < rowsNum; ++i) {
176                 this.table.rows[i].insertCell(this.curCol);
177             }
178             this.refreshColSerialNumber();
179         }
180         ExcelTable.prototype.refreshColSerialNumber = function () {
181             //real time get latest rowsNum,colsNum
182             var colsNum = this.table.rows.item(0).cells.length;
183             for (var j = 1; j < colsNum; ++j) {
184                 this.table.rows[0].cells[j].innerText = ExcelTable.calcColNum(j - 1);
185             }
186         }
187         ExcelTable.prototype.deleteRowOrCol = function () {
188             if (this.curCol == 0) {
189                 this.deleteRow();
190             }
191             else if (this.curRow == 0) {
192                 this.deleteCol();
193             }
194         }
195         ExcelTable.prototype.deleteRow = function () {
196             //real time get latest rowsNum,colsNum
197             var rowsNum = this.table.rows.length;
198             var colsNum = this.table.rows.item(0).cells.length;
199             this.table.deleteRow(this.curRow);
200             this.refreshRowSerialNumber();
201         }
202         ExcelTable.prototype.deleteCol = function () {
203             //real time get latest rowsNum,colsNum
204             var rowsNum = this.table.rows.length;
205             var colsNum = this.table.rows.item(0).cells.length;
206             for (var i = 0; i < rowsNum; ++i) {
207                 this.table.rows[i].deleteCell(this.curCol);
208             }
209             this.refreshColSerialNumber();
210         }
211         ExcelTable.prototype.showContextMenu = function (offx, offy) {
212             this.contextMenu.style.left = offx + "px";
213             this.contextMenu.style.top = offy + "px";
214             this.contextMenu.className = "show";
215         }
216         ExcelTable.prototype.hideContextMenu = function () {
217             this.contextMenu.className = "hide";
218         }
219         ExcelTable.prototype.showResizeLine = function (offx, offy) {
220             this.resizeLine.style.left = offx + "px";
221             this.resizeLine.style.top = offy + "px";
222             this.resizeLine.className = "show";
223         }
224         ExcelTable.prototype.hideResizeLine = function () {
225             this.resizeLine.className = "hide";
226         }
227         ExcelTable.prototype.contextMenuFun = function (e) {
228             this.curRow = e.target.parentElement.rowIndex;
229             this.curCol = e.target.cellIndex;
230             if (this.curRow == 0 || this.curCol == 0) {
231                 e.preventDefault();
232                 var offx = e.clientX;//==e.screenX
233                 var offy = e.clientY;//!=e.screenY
234                 this.showContextMenu(offx, offy);
235             }
236         }
237         ExcelTable.prototype.showSelectDiv = function (offx, offy, width, height) {
238             this.selectDiv.className = "show";
239             this.selectDiv.style.left = offx + "px";
240             this.selectDiv.style.top = offy + "px";
241             this.selectDiv.style.width = width + "px";
242             this.selectDiv.style.height = height + "px";
243         }
244         ExcelTable.prototype.hideSelectDiv = function () {
245             this.selectDiv.className = "hide";
246         }
247         ExcelTable.prototype.documentAddOrRemoveMouseMoveEvents = function (add) {
248             /*var self = this;
249             var handler = function (e) {
250                 self.documentMouseMoveFun(e); //keynote:handler can't use "this",becauese "this" is the context variable that refers to the element that fired the event 
251             };*/
252             if (add) {
253                 document.addEventListener('mousemove', this.handler1, false);
254             }
255             else {
256                 document.removeEventListener('mousemove', this.handler1, false);
257             }
258         }
259         ExcelTable.prototype.documentAddOrRemoveMouseUpEvents = function (add) {
260             /*var self = this;
261             var handler = function (e) {
262                 self.documentMouseUpFun(e);
263             };*/
264             if (add) {
265                 document.addEventListener('mouseup', this.handler2, false);
266             }
267             else {
268                 document.removeEventListener('mouseup', this.handler2, false);    
269             }
270         }
271         ExcelTable.prototype.documentMouseMoveFun = function (e) {    
272             this.documentMouseMoveResizeFun(e);
273         }
274         ExcelTable.prototype.documentMouseUpFun = function (e) {
275             if (this.resizeFlag) {
276                 this.documentMouseUpResizeFun(e);
277             }
278             this.documentMouseUpSelectFun(e);
279         }
280         ExcelTable.prototype.documentMouseMoveResizeFun = function (e) {
281             if (this.curRow == 0 && this.curCol != 0) {//resize column width
282                 //The maximum width of the resizeElem is not more than 300px, and the minimum is no less than 5px;
283                 if ((e.clientX - ExcelTable.getOffSet(this.resizeElem).x) <= this.maxWidthOrHeight && (e.clientX - ExcelTable.getOffSet(this.resizeElem).x) >= this.minWidthOrHeight) {
284                     this.resizeLine.style.left = e.clientX + 'px';
285                     this.upOffset = e.clientX;
286                 } else if ((e.clientX - ExcelTable.getOffSet(this.resizeElem).x) > this.maxWidthOrHeight) {
287                     this.upOffset = ExcelTable.getOffSet(this.resizeElem).x + this.maxWidthOrHeight;
288                 } else {
289                     this.upOffset = ExcelTable.getOffSet(this.resizeElem).x + this.minWidthOrHeight;
290                 }
291             }
292             else if (this.curCol == 0 && this.curRow != 0) {//resize row height
293                 //The maximum height of the resizeElem is not more than 300px, and the minimum is no less than 5px;
294                 if ((e.clientY - ExcelTable.getOffSet(this.resizeElem).y) <= this.maxWidthOrHeight && (e.clientY - ExcelTable.getOffSet(this.resizeElem).y) >= this.minWidthOrHeight) { //最大不超过300px,最小不小于5px;
295                     this.resizeLine.style.top = e.clientY + 'px';
296                     this.upOffset = e.clientY;
297                 } else if ((e.clientY - ExcelTable.getOffSet(this.resizeElem).y) > this.maxWidthOrHeight) {
298                     this.upOffset = ExcelTable.getOffSet(this.resizeElem).y + this.maxWidthOrHeight;
299                 } else {
300                     this.upOffset = ExcelTable.getOffSet(this.resizeElem).y + this.minWidthOrHeight;
301                 }
302             }
303         }
304         ExcelTable.prototype.documentMouseUpResizeFun = function (e) {
305            if (this.curRow == 0 && this.curCol != 0) {//resize column width
306                 this.resizeLine.className = "hide";
307                 var w = this.resizeElem.offsetWidth + this.upOffset - this.downOffset;
308                 //Loop to resize width
309                 var trs = this.table.rows;
310                 for (var i = 0; i < trs.length; ++i) {
311                     trs[i].cells[this.resizeElem.cellIndex].style.width = w + 'px';
312                 }
313             }
314             else if (this.curCol == 0 && this.curRow != 0) {//resize row height
315                 this.resizeLine.className = "hide";
316                 var h = this.resizeElem.offsetHeight + this.upOffset - this.downOffset;
317                 //Loop to resize height
318                 var tr = this.resizeElem.parentElement;
319                 for (var i = 0; i < tr.cells.length; ++i) {
320                     //must use next two lines to change height
321                     tr.cells[i].style.height = h + 'px';
322                     tr.cells[i].style.lineHeight = h + 'px';
323                 }    
324             }
325             this.resizeFlag = false;
326             this.table.style.cursor = "default";
327             this.resizeElem = null;
328             this.documentAddOrRemoveMouseMoveEvents(false);
329             this.documentAddOrRemoveMouseUpEvents(false);
330         }
331         ExcelTable.prototype.documentClickFun = function (e) {
332             this.hideContextMenu();
333         }
334         ExcelTable.prototype.tableMouseMoveFun = function (e) {
335             if (!this.resizeFlag) {//when  event of documentMouseMove occur,tableMouseMove also occur;so make a distinction
336                 this.tableMouseMoveResizeFun(e);
337             }
338             if (this.selFlag) {
339                 this.tableMouseMoveSelectFun(e);
340             }
341         }
342         ExcelTable.prototype.tableMouseDownFun = function (e) {
343             // deal with resize
344             if (this.resizeElem != null) {
345                 this.tableMouseDownResizeFun(e);
346             }
347             else {
348                 //deal with  selection
349                 this.tableMouseDownSelectFun(e);
350             }
351         }
352        
353         ExcelTable.prototype.tableMouseMoveResizeFun = function (e) {
354             this.curRow = e.target.parentElement.rowIndex;
355             this.curCol = e.target.cellIndex;
356             this.table.style.cursor = "default";
357             this.resizeElem = null;
358             var elem_offset;
359             if (this.curRow == 0 && this.curCol != 0) {//resize column width
360                 //Get the mouse and element position, determine whether to trigger resize, and change the mouse style
361                 //offsetX,offsetY：When an event occurs, the mouse is opposite the upper left corner of the e.target
362                 elem_offset = e.target.offsetWidth;
363                 if (elem_offset - e.offsetX <= 3) {
364                     this.resizeElem = e.target;
365                     this.table.style.cursor = 'e-resize'; //resizeElem.style.cursor = 'e-resize';--error,The cursor style  is valid on the entire table, otherwise the cursor style is out of reach after the resizeElem
366                 } else if ((e.offsetX <= 3) && (this.curCol > 1)) {
367                     this.resizeElem = e.target.previousSibling;
368                     this.table.style.cursor = 'e-resize';
369                 } 
370             }
371             else if (this.curCol == 0 && this.curRow != 0) {//resize row height
372                 elem_offset = e.target.offsetHeight;
373                 if (elem_offset - e.offsetY <= 3) {
374                     this.resizeElem = e.target;
375                     this.table.style.cursor = 's-resize';
376 
377                 } else if ((e.offsetY <= 3) && (this.curRow > 1)) {
378                     //find e.target Previous column corresponding element
379                     this.resizeElem = this.table.rows[this.curRow - 1].cells[this.curCol];
380                     this.table.style.cursor = 's-resize';
381                 } 
382             }
383             //TD element not handled 
384         }
385         ExcelTable.prototype.tableMouseDownResizeFun = function (e) {
386             if (this.table.style.cursor == 'e-resize') {//resize column width
387                 this.resizeFlag = true;
388                 this.resizeLine.style.left = ExcelTable.getOffSet(this.resizeElem).x + this.resizeElem.offsetWidth + 'px'; //The resize line should appear on the right edge of the element
389                 this.resizeLine.style.width = "0px";
390                 this.resizeLine.style.height = this.table.offsetHeight + 'px'; 
391                 this.resizeLine.style.top = ExcelTable.getOffSet(this.table).y + 'px'; 
392                 this.resizeLine.style.borderLeft = "dashed 1px red";
393                 this.resizeLine.className = "show";
394                 this.downOffset = ExcelTable.getOffSet(this.resizeElem).x + this.resizeElem.offsetWidth;
395             }
396             else if (this.table.style.cursor == 's-resize') {//resize row height
397                 this.resizeFlag = true;
398                 this.resizeLine.style.left = ExcelTable.getOffSet(this.table).x + 'px'; ;
399                 this.resizeLine.style.width = this.table.offsetWidth + 'px'; 
400                 this.resizeLine.style.height = "1px";
401                 this.resizeLine.style.top = ExcelTable.getOffSet(this.resizeElem).y + this.resizeElem.offsetHeight + 'px'; //The resize line should appear on the bottom edge of the element
402                 this.resizeLine.style.borderTop = "dashed 1px red";
403                 this.resizeLine.className = "show";
404                 this.downOffset = ExcelTable.getOffSet(this.resizeElem).y + this.resizeElem.offsetHeight;
405             }
406             this.documentAddOrRemoveMouseMoveEvents(true);
407             this.documentAddOrRemoveMouseUpEvents(true);
408         }
409 
410         ExcelTable.prototype.tableMouseDownSelectFun = function (e) {
411             if (e.target == this.table) return; //Moving outside of the table, is this.table
412             if (e.target == this.allImg) return; //e.target isn't img
413             //if selSrcElem is th,then selDesElem can be th or td;
414             //But, selSrcElem is td,then selDesElem must is td;
415             this.selFlag = true;
416             this.selSrcElem = e.target;
417             this.selDesElem = e.target;
418             this.documentAddOrRemoveMouseUpEvents(true);
419         }
420         ExcelTable.prototype.tableMouseMoveSelectFun = function (e) {
421             if (e.target == this.table) return;
422             if (e.target == this.allImg) return;
423             if ((this.selSrcElem.tagName == "TD") && (e.target.tagName != "TD")) return;
424             this.selDesElem = e.target;
425             this.calSelectPositionFun();
426         }
427         ExcelTable.prototype.calSelectPositionFun = function () {
428             var selSrcRow = this.selSrcElem.parentElement.rowIndex;
429             var selSrcCol = this.selSrcElem.cellIndex;
430             var selDesRow = this.selDesElem.parentElement.rowIndex;
431             var selDesCol = this.selDesElem.cellIndex;
432 
433             var srcOffx = ExcelTable.getOffSet(this.selSrcElem).x;
434             var srcOffy = ExcelTable.getOffSet(this.selSrcElem).y;
435             var DesOffx = ExcelTable.getOffSet(this.selDesElem).x;
436             var DesOffy = ExcelTable.getOffSet(this.selDesElem).y;
437             var divwidtd = (DesOffx > srcOffx) ? this.selDesElem.offsetWidth : this.selSrcElem.offsetWidth;
438             var divheight = (DesOffy > srcOffy) ? this.selDesElem.offsetHeight : this.selSrcElem.offsetHeight;
439 
440             if ((selSrcRow != 0 && selSrcCol != 0) && (selDesRow != 0 && selDesCol != 0)) {
441                 this.showSelectDiv(Math.min(srcOffx, DesOffx), Math.min(srcOffy, DesOffy), Math.abs(DesOffx - srcOffx) + divwidtd, Math.abs(DesOffy - srcOffy) + divheight);
442             }
443             else if ((selSrcCol == 0 && selSrcRow != 0) && (selDesRow != 0)) {//选择行
444                 this.showSelectDiv(ExcelTable.getOffSet(this.selSrcElem).x, Math.min(srcOffy, DesOffy), this.table.offsetWidth, Math.abs(DesOffy - srcOffy) + divheight);
445             }
446             else if ((selSrcRow == 0 && selSrcCol != 0) && (selDesCol != 0)) {//选择行
447                 this.showSelectDiv(Math.min(srcOffx, DesOffx), ExcelTable.getOffSet(this.selSrcElem).y, Math.abs(DesOffx - srcOffx) + divwidtd, this.table.offsetHeight);
448             }
449         }
450         ExcelTable.prototype.documentMouseUpSelectFun = function (e) {
451             // selDesElem is the last valid value in tableMouseMoveSelectFun
452             this.selFlag = false;
453             if (this.selSrcElem == null) return;
454             this.calSelectPositionFun();
455             this.documentAddOrRemoveMouseUpEvents(false);
456         }
457         ExcelTable.prototype.initTable = function () {
458             var elemTd = null;
459             var elemTr = null;
460             for (var i = 0; i < this.initRow; ++i) {
461                 elemTr = document.createElement("tr");
462                 for (var j = 0; j < this.initCol; ++j) {
463                     if (i == 0 && j == 0) {
464                         elemTd = document.createElement("th");
465                         elemTd.className = "rowth";
466                         this.allImg = document.createElement("img");
467                         this.allImg.src = "img/all.jpg";
468                         elemTd.appendChild(this.allImg);
469                     }
470                     else if (i == 0) {
471                         elemTd = document.createElement("th");
472                         elemTd.className = "colth";
473                         elemTd.innerText = ExcelTable.calcColNum(j - 1);
474                     }
475                     else if (j == 0) {
476                         elemTd = document.createElement("th");
477                         elemTd.className = "rowth";
478                         elemTd.innerText = i;
479                     }
480                     else {
481                         elemTd = document.createElement("td");
482                     }
483                     elemTr.appendChild(elemTd);
484                 }
485                 this.table.appendChild(elemTr);
486             }
487         }
488         ExcelTable.prototype.initContextMenu = function () {
489             this.contextMenu = document.createElement("div");
490             this.contextMenu.id = "contextmenu";
491             var elemInsert = document.createElement("div");
492             elemInsert.innerText = "insert";
493             this.contextMenu.appendChild(elemInsert);
494             var elemDelete = document.createElement("div");
495             elemDelete.innerText = "delete";
496             this.contextMenu.appendChild(elemDelete);
497             //var self = this;
498             //elemInsert.addEventListener("click", function () {
499             //    self.insertRowOrCol();
500             //});//Two methods are available
501             elemInsert.addEventListener("click", (function (me) {
502                 return function () {
503                     me.insertRowOrCol();
504                 };
505             })(this));
506             var self = this;
507             elemDelete.addEventListener("click", function () {
508                 self.deleteRowOrCol();
509             });
510             document.body.appendChild(this.contextMenu);
511             this.hideContextMenu();
512         }
513         ExcelTable.prototype.initResizeLine = function () {
514             this.resizeLine = document.createElement('div');
515             this.resizeLine.id = "resizeline";
516             document.body.appendChild(this.resizeLine);
517             this.hideResizeLine();
518         }
519         ExcelTable.prototype.initSelectDiv = function () {
520             this.selectDiv = document.createElement('div');
521             this.selectDiv.id = "selectdiv";
522             document.body.appendChild(this.selectDiv);
523             this.hideSelectDiv();
524 
525         }
526         ExcelTable.prototype.init = function () {
527             //initialize table
528             this.initTable();
529             //initialize contextmenu
530             this.initContextMenu();
531             //initialize resizeLine
532             this.initResizeLine();
533             //initialize selectDiv
534             this.initSelectDiv();
535             
536             this.addEvents = (function (self) {
537                 self.table.addEventListener("contextmenu", function (e) {
538                     self.contextMenuFun(e);
539                 });
540                 self.table.addEventListener("mousemove", function (e) {
541                     self.tableMouseMoveFun(e);
542                 });
543                 self.table.addEventListener("mousedown", function (e) {
544                     self.tableMouseDownFun(e);
545                 });
546 
547                 document.addEventListener("click", function (e) {
548                     self.documentClickFun(e);
549                 });
550             })(this);
551         }
552     </script>
553 </head>
554 <body>
555     <table id="maintable"></table>
556 </body>
557 </html>
    View Code

    实现的功能如下：

    1.插入，删除

    2.改变列宽和行高

    3.选择功能

    存在的bug:当执行了操作2和3之后，再执行1，行高会改变，选择区域也无法刷新。

    学到的知识：

    1. 尽量不用innerHTML,代码不清楚，耗费编译资源大，用innerText取代，或者使用createElement

    2.js中少修改style,可以通过添加className来修改，前提是在css中设定好.class 的样式

    3.事件之间的关系：鼠标move事件documentMouseMove和tableMouseMove都会触发，置于执行顺序这就涉及到冒泡与捕获的关系

                             oncontext会触发mousedown,mouseup等

                             onclick和ondbclick会同时存在，一般通过在oclick中加timeout来区分，后续学习。

    4.事件响应函数中的this,两种方法,不能直接使用this,因为this始终指向当前上下文，对于事件响应函数中的this只当前响应元素。

    　　　　elemInsert.addEventListener("click", (function (me) {
    　　　　　　return function () {
    　　　　　　　　me.insertRowOrCol();
    　　　　　　};
    　　　　})(this));


    　　　　var self = this;
    　　　　elemDelete.addEventListener("click", function () {
    　　　　　　self.deleteRowOrCol();
    　　　　});

    5.js函数类 哪些设为成员变量（每个对象都需要单独有一份），哪些设为类的方法（工具方法），哪些设为原型方法

    6.修改表格的行列高：

    //Loop to resize width
    var trs = this.table.rows;
    for (var i = 0; i < trs.length; ++i) {
    trs[i].cells[this.resizeElem.cellIndex].style.width = w + 'px';
    }

    //Loop to resize height
    var tr = this.resizeElem.parentElement;
    for (var i = 0; i < tr.cells.length; ++i) {
    //must use next two lines to change height
    tr.cells[i].style.height = h + 'px';
    tr.cells[i].style.lineHeight = h + 'px';
    }

    7.两个重要的属性：

     pointer-events: none;//表示它将捕获不到任何点击，而只是让事件穿透到它的下面。

    user-select: none;//文本不能被选择

    8.参数，默认参数

    在Javascript中， 函数定义的参数个数， 与调用时传入的参数个数，是可以不同的．
    一般情况下，在定义函数时，将必须传入的参数放在前面， 可选的参数放在后面．在函数体内部需要对参数的传入情况作判断，以防参数不存在时程序出错．
    例如
    function js(x, y, z) {
     this.x = x || 0;//或者this.span = (undefined == span) ? 3 : span;
       this.y = y || 0;
       this.z = z || 0;
    }

    调用时可以传入0-3个参数都不会出错，但传参的顺序是已经定了的．
    比如：
    var A = new js();   //A.x=0, A.y=0, A.z=0
    var A=new js(5, 3);  //A.x=5, A.y=3, A.z=0

    如果只想传递参数y, 则必须传递两个参数，其中第一个可传入null或0

    如x是可选y是必选，建议在定义函数时改变形参的顺序

    9.几个变量：elem.offsetLeft，elem.offsetTop，elem.offsetParent

                    elem.offsetWidth,elem.offsetHeight,

                    e.offsetX，e.offsetY

                    e.screenX,e.screenY

    10,尽量使用addEventListener和removeEventListener，少用onclick方法添加事件响应函数，因为onclick方法会存在覆盖行为，前者可以添加多个事件处理程序

    注意：addEventListener和removeEventListener中第二个参数指向的函数必须是同一个，因此必须在外面定义好handler,才能确保使用的是同一个函数，如果在内部分别定义，及时函数体相同，也是指向不同位置的不同函数。详细可参见代码中例子。

    问题：addEventListener和removeEventListener次数不对称会怎样？

    通过addEventListener()添加的事件处理程序只能使用removeEventListener()来移除；移除时传入的参数与添加处理程序时使用的参数相同。这也意味着通过addEventListener()添加的匿名函数无法移除，如下面的例子所示：

    复制代码
    var btn = document.getElementById("myBtn");
btn.addEventListener("click", function () {
    alert(this.id);
}, false);
btn.removeEventListener("click", function () {  //无效！
    alert(this.id);
}, false);

    11.表格操作：

    获取当前元素行列号：this.curRow = e.target.parentElement.rowIndex;
                                this.curCol = e.target.cellIndex;

    获取表格行列数： var rowsNum = this.table.rows.length;
    　　　　　　　　 var colsNum = this.table.rows.item(0).cells.length;

    插入行：

       　　var row = this.table.insertRow(this.curRow);
    　　　　for (var i = 1; i < colsNum; ++i) {
    　　　　row.insertCell(i);
    　　　　}

    删除行：this.table.deleteRow(this.curRow);

    插入列：

    　　for (var i = 0; i < rowsNum; ++i) {
    　　this.table.rows[i].insertCell(this.curCol);
    　　}

    删除列：

    　　for (var i = 0; i < rowsNum; ++i) {
    　　this.table.rows[i].deleteCell(this.curCol);
    　　}

    12.消息处理事件函数参数必须写上e,负责函数体内默认的e为全局event对象，类似window对象

    需要继续学习：

    1.table 布局  其属性：width height overFlow:scroll

    给 thead tbody tfoot上添加事件

    2.JS浮点数运算
  • 相关阅读:
    应用express mockjs模拟前端json数据接口
    sublime text3 cssrem 快速px转rem插件
    python多版本共存问题（以2.7和3.5系列版本为例）
    免费的大数据学习资料，这一份就足够
    大数据时代的三大趋势和三大困境
    四个填空题，你会如何回答怎么学大数据？看看阿里的大数据学习！
    为什么学习大数据，大数据专家写给大数据分析学习者的10个理由
    你知道大数据强大在哪里！！！你永远也不会猜到
    大数据的强大你知道多少
    零基础入门到精通：Python大数据与机器学习之Pandas-数据操作
  • 原文地址：https://www.cnblogs.com/Yogurshine/p/6985405.html
Copyright © 2020-2023  润新知