得到对象的键名：
var arr={a:12,b:34,c:534,d:3344}; var srr=[]; var i=0; for(var items in arr){ srr[i]=items;i++; } // srr=["a", "b", "c", "d"];
jquery操作cookie
$.cookie(’name’, ‘value’, {expires: 7, path: ‘/’, domain: ‘jquery.com’, secure: true});
jquery 阻塞超链接执行，button等同效
$('.a').click(function(e){
e.preventDefault();
});
jQuery选择器： name^='aaa' 是以aaa为开头查找，匹配 aaa, aaab, aaaacd, aaa_etc
jQuery(haha).find("input[title],select[title][name^='DATA_'],textarea[title]")
jQuery(haha).find("input[type=hidden]:gt(5):lt(19)")
数组转换字符串
var arr = [ "a", "b", "c", "d", "e" ]; var ss=arr.join(", "); ss="a, b, c, d, e"
javascript 生成定长的62进制随机码（0-9, a-z, A-Z）
function getRandom(param){ str=[ "0","1","2","3","4","5","6","7","8","9",
"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",
"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"]; key = "";
for(i=0;i<param;i++) { key += str[Math.floor(Math.random()*61)]; //1-62 //生成php随机数 } return key; } getRandom(32);
javascript 复制对象，直接赋值只是引用地址，修改一个另一个也会有影响，如果要不影响的话要用new Object(obj)来生成
var s1={name:1}; var s2=s1; //s2={name:1},s1={name:1}; s1.name=2; s1={name:2},s2={name:2}; //s1 s2指向同一个地址 var s1={name:1}; var s2=new Object(s1); //s2={name:1},s1={name:1}; s1.name=2; //s2={name:1},s1={name:1};
字符串替换，repalce只能换第一个，如果要全部换要用正则
var string = "john john"; console.log(string.replace(/hn/, "ana")); // "joana john" console.log(string.replace(/hn/g, "ana")); // "joana joana"
stringify把javascript对象转换成json字符串
parse把json字符串转换成javascript对象，如果 parse不行就用eval()，但eval有风险，会执行function
JSON.stringify();
JSON.parse();
监听键盘事件：下面有部分对照表
ESC 27
A 65
B 66
...
Z 90
shift 16
ctrl 17
alt 18
win 91
.on('keydown', function (e) {
//do sth
})
javascript 判断元素是否在数组中（有，返回index， 没有，返回-1）
function in_array(str, arr) { length = arr.length for (var i = 0; i < length; i++) { if (str === arr[i]) { return i; } } return -1; }
setTimeout 会开启新的线程，有时候可以直接用do while监听
do{}while(jQuery("#flow_id option").length==0)
window.open，打开一个新的页面，这个新开的页面可以通过js去关掉
参数表：
| height | 高 |
| width | 宽 |
| top | 距屏顶 |
| left | 距屏左 |
| toolbar | 工具条 |
| menubar | 菜单条 |
| scrollbars | 滚动条 |
| resizable | 调整大小 |
| location | 地址栏 |
| status | 状态样 |
window.open ('page.html','newwindow','height=100,width=400,top=0,left=0,toolbar=no,menubar=no,scrollbars=no, resizable=no,location=no, status=no')
IE5 position:fixed;
一定要使用旧标准的html文档。 不然fixed失效。
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html> <head></head> <body></body> </html>
旧IE 模拟placeholder：
<input name="name" id="name" onFocus="if (value =='学生姓名'){value =''}" onBlur="if (value ==''){value='学生姓名'}" required />
js 计数器，然后每次直接c1();就能进行计数了。
function create_a_counter() { var count = 0; return function(){ count = count +1; return count; } } var c1=create_a_counter();
上面的计数器改进代码，构造化：
function counter(){ var count = 0; function doplus(){ count=count+1;return count; } function dominus(){ count = count-1;return count; } var publicAPI={ plus:doplus,minus:dominus } return publicAPI; }
动态加载js代码：
function InsertJs(strUrl ,fOnload) { var script = document.createElement("script"); script.type = "text/javascript"; script.src = strUrl; script.charset = "UTF-8"; if (fOnload) { script.onload = fOnload; } document.body.appendChild(script); } InsertJs("http://xxx.com/js/test.js");
js实现文字超出部分用省略号代替
function cutString(str, len) { //length属性读出来的汉字长度为1 if(str.length*2 <= len) { return str; } var strlen = 0; var s = ""; for(var i = 0;i < str.length; i++) { s = s + str.charAt(i); if (str.charCodeAt(i) > 128) { strlen = strlen + 2; if(strlen >= len){ return s.substring(0,s.length-1) + "..."; } } else { strlen = strlen + 1; if(strlen >= len){ return s.substring(0,s.length-2) + "..."; } } } return s; }
具体实现
function jcutstring(obj, limit){ var len = obj.length; for(i=0 ;i<len; i++){ obj.eq(i).text(cutString(obj.eq(i).text(), limit)); } }; $(document).ready(function(){ var href = $(".aaa"); jcutstring(href, 30); });
window.haha 是个对象，在chrome中的console打 haha 与 window.haha 出来的都是function haha的定义。
所以以下三行其实是一样的，可以通过这种方法动态调用函数
haha();
window.haha();
window["haha"]();
js 检查js css是否加载
function isInclude(name){ var js= /js$/i.test(name); var es=document.getElementsByTagName(js?'script':'link'); for(var i=0;i<es.length;i++) if(es[i][js?'src':'href'].indexOf(name)!=-1)return true; return false; }
不能右键与选中的网页解决方法：
把以下代码复制到地址栏中：
javascript:document.oncontextmenu=new Function("event.returnValue=true;");document.onselectstart=new Function("event.returnValue=true;");
jQuery HTML 转义
jQuery.parseHTML(cnt)
js 去重排序，对定范围的序列进行排序时，效率不错。
function notsort(list){ var haha=[],result=[]; for(var i=0;i<list.length;i++){ haha[list[i]]=list[i]; } for(var i=0;i<haha.length;i++){ if(haha[i]){ result.push(haha[i]); } } return result; }