有关类的操作

 1 function getByClass(obj,sClass){
 2     if(obj.getElementsByClassName){
 3         return obj.getElementsByClassName(sClass);
 4     }else{
 5         var arr=[];
 6         //var reg=/sClass/;
 7         var reg=new RegExp('\b'+sClass+'\b');
 8         var aEle=obj.getElementsByTagName('*');
 9 
10         for(var i=0; i<aEle.length; i++){
11             if(reg.test(aEle[i].className)){
12                 arr.push(aEle[i]);
13             }
14         }
15         return arr;
16     }
17 }
18 
19 function hasClass(obj,sClass){
20     var reg=new RegExp('\b'+sClass+'\b');
21     return reg.test(obj.className);
22 }
23 
24 function addClass(obj,sClass){
25     if(obj.className){
26         if(!hasClass(obj,sClass)){
27             obj.className+=' '+sClass;
28         }
29     }else{
30         obj.className=sClass;
31     }
32 }
33 
34 function removeClass(obj,sClass){
35     var reg=new RegExp('\b'+sClass+'\b','g');
36     if(hasClass(obj,sClass)){
37         obj.className=obj.className.replace(reg,'').replace(/^s+|s+$/g,'').replace(/s+/g,' ');
38     }
39 }
40 
41 function toggleClass(obj,sClass){
42     if(hasClass(obj,sClass)){
43         removeClass(obj,sClass);
44     }else{
45         addClass(obj,sClass);
46     }
47 }