<script> //----------------for用來遍歷數(shù)組對象-- var i,myArr = [1,2,3]; for (var i = 0; i < myArr.length; i++) {  console.log(i+":"+myArr[i]); }; //---------for-in 用來遍歷非數(shù)組對象 var man ={hands:2,legs:2,heads:1}; //為所有的對象添加clone方法，即給內(nèi)置原型(object,Array,function)增加原型屬性,該方法很強(qiáng)大，也很危險(xiǎn) if(typeof Object.prototype.clone ==="undefined"){  Object.prototype.clone = function(){};  } // for(var i in man){  if (man.hasOwnProperty(i)) { //filter,只輸出man的私有屬性   console.log(i,":",man[i]);  }; } //輸出結(jié)果為print hands:2,legs:2,heads:1 for(var i in man) {//不使用過濾  console.log(i,":",man[i]); }  //輸出結(jié)果為 //hands : 2 index.html:20 //legs : 2 index.html:20 //heads : 1 index.html:20 //clone : function (){}  for(var i in man) {  if(Object.prototype.hasOwnProperty.call(man,i)) { //過濾   console.log(i,":",man[i]);  } } //輸出結(jié)果為print hands:2,legs:2,heads:1 </script>