function $(id)冲突

这个问题很简单，不过惭愧的是我到今天才发现。

如果已经用了JQUERY，也就是HEAD里面已经引用了JQUERY，那么这个页面中那些和JQUERY没有任何关系的原生JS就不可以再使用除JUQERY的选择器缩写符号$了。

那么怎么办呢？

比如这一段JS：

// JavaScript Document
function $(id) { return document.getElementById(id); }
function addLoadEvent(func){
 var oldonload = window.onload;
 if (typeof window.onload != 'function') {
  window.onload = func;
 } else {
  window.onload = function(){
   oldonload();
   func();
  }
 }
}
function moveElement(elementID,final_x,final_y,interval) {
  if (!document.getElementById) return false;
  if (!document.getElementById(elementID)) return false;
  var elem = document.getElementById(elementID);
  if (elem.movement) {
    clearTimeout(elem.movement);
  }
  if (!elem.style.left) {
    elem.style.left = "0px";
  }
  if (!elem.style.top) {
    elem.style.top = "0px";
  }
  var xpos = parseInt(elem.style.left);
  var ypos = parseInt(elem.style.top);
  if (xpos == final_x && ypos == final_y) {
  return true;
  }
  if (xpos < final_x) {
    var dist = Math.ceil((final_x - xpos)/10);
    xpos = xpos + dist;
  }
  if (xpos > final_x) {
    var dist = Math.ceil((xpos - final_x)/10);
    xpos = xpos - dist;
  }
  if (ypos < final_y) {
    var dist = Math.ceil((final_y - ypos)/10);
    ypos = ypos + dist;
  }
  if (ypos > final_y) {
    var dist = Math.ceil((ypos - final_y)/10);
    ypos = ypos - dist;
  }
  elem.style.left = xpos + "px";
  elem.style.top = ypos + "px";
  var repeat = "moveElement('"+elementID+"',"+final_x+","+final_y+","+interval+")";
  elem.movement = setTimeout(repeat,interval);
}
function classNormal(iFocusBtnID,iFocusTxID){
 var iFocusBtns= $(iFocusBtnID).getElementsByTagName('li');
 var iFocusTxs = $(iFocusTxID).getElementsByTagName('li');
 for(var i=0; i<iFocusBtns.length; i++) {
  iFocusBtns[i].className='normal';
  iFocusTxs[i].className='normal';
 }
}
function classCurrent(iFocusBtnID,iFocusTxID,n){
 var iFocusBtns= $(iFocusBtnID).getElementsByTagName('li');
 var iFocusTxs = $(iFocusTxID).getElementsByTagName('li');
 iFocusBtns[n].className='current';
 iFocusTxs[n].className='current';
}
function iFocusChange() {
 if(!$('ifocus')) return false;
 $('ifocus').onmouseover = function(){atuokey = true};
 $('ifocus').onmouseout = function(){atuokey = false};
 var iFocusBtns = $('ifocus_btn').getElementsByTagName('li');
 var listLength = iFocusBtns.length;
 iFocusBtns[0].onmouseover = function() {
  moveElement('ifocus_piclist',0,0,5);
  classNormal('ifocus_btn','ifocus_tx');
  classCurrent('ifocus_btn','ifocus_tx',0);
 }
 if (listLength>=2) {
  iFocusBtns[1].onmouseover = function() {
   moveElement('ifocus_piclist',0,-366,5);
   classNormal('ifocus_btn','ifocus_tx');
   classCurrent('ifocus_btn','ifocus_tx',1);
  }
 }
 if (listLength>=3) {
  iFocusBtns[2].onmouseover = function() {
   moveElement('ifocus_piclist',0,-732,5);
   classNormal('ifocus_btn','ifocus_tx');
   classCurrent('ifocus_btn','ifocus_tx',2);
  }
 }
 if (listLength>=4) {
  iFocusBtns[3].onmouseover = function() {
   moveElement('ifocus_piclist',0,-1098,5);
   classNormal('ifocus_btn','ifocus_tx');
   classCurrent('ifocus_btn','ifocus_tx',3);
  }
 }
}
setInterval('autoiFocus()',5000);
var atuokey = false;
function autoiFocus() {
 if(!$('ifocus')) return false;
 if(atuokey) return false;
 var focusBtnList = $('ifocus_btn').getElementsByTagName('li');
 var listLength = focusBtnList.length;
 for(var i=0; i<listLength; i++) {
  if (focusBtnList[i].className == 'current') var currentNum = i;
 }
 if (currentNum==0&&listLength!=1 ){
  moveElement('ifocus_piclist',0,-366,5);
  classNormal('ifocus_btn','ifocus_tx');
  classCurrent('ifocus_btn','ifocus_tx',1);
 }
 if (currentNum==1&&listLength!=2 ){
  moveElement('ifocus_piclist',0,-732,5);
  classNormal('ifocus_btn','ifocus_tx');
  classCurrent('ifocus_btn','ifocus_tx',2);
 }
 if (currentNum==2&&listLength!=3 ){
  moveElement('ifocus_piclist',0,-1098,5);
  classNormal('ifocus_btn','ifocus_tx');
  classCurrent('ifocus_btn','ifocus_tx',3);
 }
 if (currentNum==3 ){
  moveElement('ifocus_piclist',0,0,5);
  classNormal('ifocus_btn','ifocus_tx');
  classCurrent('ifocus_btn','ifocus_tx',0);
 }
 if (currentNum==1&&listLength==2 ){
  moveElement('ifocus_piclist',0,0,5);
  classNormal('ifocus_btn','ifocus_tx');
  classCurrent('ifocus_btn','ifocus_tx',0);
 }
 if (currentNum==2&&listLength==3 ){
  moveElement('ifocus_piclist',0,0,5);
  classNormal('ifocus_btn','ifocus_tx');
  classCurrent('ifocus_btn','ifocus_tx',0);
 }
}
addLoadEvent(iFocusChange);

如果既要用到这段JS，又想调用JS库模块，并且该库已经把$当成了ID选择器，那么，只要将上面这段中的$全部替换成自己想要取的函数名字就可以了：

像这样：

// JavaScript Document
function getObj(id) { return document.getElementById(id); }
function addLoadEvent(func){
 var oldonload = window.onload;
 if (typeof window.onload != 'function') {
  window.onload = func;
 } else {
  window.onload = function(){
   oldonload();
   func();
  }
 }
}
function moveElement(elementID,final_x,final_y,interval) {
  if (!document.getElementById) return false;
  if (!document.getElementById(elementID)) return false;
  var elem = document.getElementById(elementID);
  if (elem.movement) {
    clearTimeout(elem.movement);
  }
  if (!elem.style.left) {
    elem.style.left = "0px";
  }
  if (!elem.style.top) {
    elem.style.top = "0px";
  }
  var xpos = parseInt(elem.style.left);
  var ypos = parseInt(elem.style.top);
  if (xpos == final_x && ypos == final_y) {
  return true;
  }
  if (xpos < final_x) {
    var dist = Math.ceil((final_x - xpos)/10);
    xpos = xpos + dist;
  }
  if (xpos > final_x) {
    var dist = Math.ceil((xpos - final_x)/10);
    xpos = xpos - dist;
  }
  if (ypos < final_y) {
    var dist = Math.ceil((final_y - ypos)/10);
    ypos = ypos + dist;
  }
  if (ypos > final_y) {
    var dist = Math.ceil((ypos - final_y)/10);
    ypos = ypos - dist;
  }
  elem.style.left = xpos + "px";
  elem.style.top = ypos + "px";
  var repeat = "moveElement('"+elementID+"',"+final_x+","+final_y+","+interval+")";
  elem.movement = setTimeout(repeat,interval);
}
function classNormal(iFocusBtnID,iFocusTxID){
 var iFocusBtns= getObj(iFocusBtnID).getElementsByTagName('li');
 var iFocusTxs = getObj(iFocusTxID).getElementsByTagName('li');
 for(var i=0; i<iFocusBtns.length; i++) {
  iFocusBtns[i].className='normal';
  iFocusTxs[i].className='normal';
 }
}
function classCurrent(iFocusBtnID,iFocusTxID,n){
 var iFocusBtns= getObj(iFocusBtnID).getElementsByTagName('li');
 var iFocusTxs = getObj(iFocusTxID).getElementsByTagName('li');
 iFocusBtns[n].className='current';
 iFocusTxs[n].className='current';
}
function iFocusChange() {
 if(!getObj('ifocus')) return false;
 getObj('ifocus').onmouseover = function(){atuokey = true};
 getObj('ifocus').onmouseout = function(){atuokey = false};
 var iFocusBtns = getObj('ifocus_btn').getElementsByTagName('li');
 var listLength = iFocusBtns.length;
 iFocusBtns[0].onmouseover = function() {
  moveElement('ifocus_piclist',0,0,5);
  classNormal('ifocus_btn','ifocus_tx');
  classCurrent('ifocus_btn','ifocus_tx',0);
 }
 if (listLength>=2) {
  iFocusBtns[1].onmouseover = function() {
   moveElement('ifocus_piclist',0,-366,5);
   classNormal('ifocus_btn','ifocus_tx');
   classCurrent('ifocus_btn','ifocus_tx',1);
  }
 }
 if (listLength>=3) {
  iFocusBtns[2].onmouseover = function() {
   moveElement('ifocus_piclist',0,-732,5);
   classNormal('ifocus_btn','ifocus_tx');
   classCurrent('ifocus_btn','ifocus_tx',2);
  }
 }
 if (listLength>=4) {
  iFocusBtns[3].onmouseover = function() {
   moveElement('ifocus_piclist',0,-1098,5);
   classNormal('ifocus_btn','ifocus_tx');
   classCurrent('ifocus_btn','ifocus_tx',3);
  }
 }
}
setInterval('autoiFocus()',5000);
var atuokey = false;
function autoiFocus() {
 if(!getObj('ifocus')) return false;
 if(atuokey) return false;
 var focusBtnList = getObj('ifocus_btn').getElementsByTagName('li');
 var listLength = focusBtnList.length;
 for(var i=0; i<listLength; i++) {
  if (focusBtnList[i].className == 'current') var currentNum = i;
 }
 if (currentNum==0&&listLength!=1 ){
  moveElement('ifocus_piclist',0,-366,5);
  classNormal('ifocus_btn','ifocus_tx');
  classCurrent('ifocus_btn','ifocus_tx',1);
 }
 if (currentNum==1&&listLength!=2 ){
  moveElement('ifocus_piclist',0,-732,5);
  classNormal('ifocus_btn','ifocus_tx');
  classCurrent('ifocus_btn','ifocus_tx',2);
 }
 if (currentNum==2&&listLength!=3 ){
  moveElement('ifocus_piclist',0,-1098,5);
  classNormal('ifocus_btn','ifocus_tx');
  classCurrent('ifocus_btn','ifocus_tx',3);
 }
 if (currentNum==3 ){
  moveElement('ifocus_piclist',0,0,5);
  classNormal('ifocus_btn','ifocus_tx');
  classCurrent('ifocus_btn','ifocus_tx',0);
 }
 if (currentNum==1&&listLength==2 ){
  moveElement('ifocus_piclist',0,0,5);
  classNormal('ifocus_btn','ifocus_tx');
  classCurrent('ifocus_btn','ifocus_tx',0);
 }
 if (currentNum==2&&listLength==3 ){
  moveElement('ifocus_piclist',0,0,5);
  classNormal('ifocus_btn','ifocus_tx');
  classCurrent('ifocus_btn','ifocus_tx',0);
 }
}
addLoadEvent(iFocusChange);

此处用getObj替代$，那么这段JS将不再与JQUERY之类的JS库冲突。

如果要优化，由于JQUERY的引入，甚至可以用$替换掉其中的getElementsByTagName或者getElementById。