参考: 只遍历出JScript对象的expando属性
处了object的hasOwnProperty方法可以获得JScript对象的expando属性外,还可以通过for in 遍历来实现。代码如下:
<script type="text/javascript"> Object.prototype.Clone = function() {}; Object.prototype.Call = function() {}; Object.prototype.OtherMethod = function(){}; Object.prototype.getExpandoNames = function() { var values = new Array(); var obj = new this.constructor(); for(var i in this) { if(obj[i]!=this[i]) { values.push(i); } } return values; } var objMap = {}; objMap['abc'] = '1.abc'; objMap['def'] = '2.def'; objMap['ghi'] = '3.ghi'; objMap['jkl'] = '4.jkl'; var exp_names = objMap.getExpandoNames(); document.write("<br>如果只需要Expando属性值,不需要prototype属性值<br>"); for(var i=0;i<exp_names.length;i++) { document.write("name: "+exp_names[i]+", value: "+objMap[exp_names[i]]+"<br>"); } </script>
如果想模仿hashtable,可以获取key以及对应的name,则可以这么写;
<script type="text/javascript"> Object.prototype.Clone = function() {}; Object.prototype.Call = function() {}; Object.prototype.OtherMethod = function(){}; Object.prototype.getExpandoValues = function() { var values = new Array(); var obj = new this.constructor(); for(var i in this) { if(obj[i]!==this[i]) { values.push({"name":i, "value":this[i]}); } } return values; } var objMap = {}; objMap['abc'] = '1.abc'; objMap['def'] = '2.def'; objMap['ghi'] = '3.ghi'; objMap['jkl'] = '4.jkl'; //var map_o = objMap['getExpandoValues'](); var map_o = objMap.getExpandoValues(); document.write("map_o.length: "+map_o.length+"<br>"); for(var i=0;i<map_o.length;i++) { //只需要Expando属性值,不需要prototype属性值 document.write("name: "+map_o[i].name+", value: "+map_o[i].value+"<br>"); } //注意不要下下面的代码,下面的输出将包含Expando属性值以及prototype属性值 for(var item in map_o){ document.write("key: "+map_o[item].name+", map[key]: "+map_o[item].value +"<br>"); } for(var item in objMap){//将包含Expando属性值以及prototype属性值 document.write(item+"<br>"); } </script>
如果不需要map的key以及value,那就不要这么麻烦,直接用hasOwnProperty属性就可以了:
<script type="text/javascript"> Object.prototype.Clone = function() {}; Object.prototype.Call = function() {}; Object.prototype.OtherMethod = function(){}; function GetExpandoValues(map) { var values = []; for ( var key in map ) { if ( map.hasOwnProperty(key) ) { values.push(map[key]); } } return values; } var objMap = {}; objMap['abc'] = '1.abc'; objMap['def'] = '2.def'; objMap['ghi'] = '3.ghi'; objMap['jkl'] = '4.jkl'; var b =GetExpandoValues(objMap); document.write("<br>直接通过hasOwnProperty属性来过滤 <br>b.length:"+b.length); document.write("<br>b"+b); </script>