集合转数组函数

 1 function toArray(coll) {
 2     for (var i = 0, a = [], len = coll.length; i < len; i++) {
 3         a[i] = coll[i];
 4     }
 5     return a;
 6 }
 7 
 8 //用法
 9 var coll = document.getElementsByTagName('div');
10 var arr = toArray(coll);