如何遍历对象属性并返回值？

如有对象
a = {
         name:"text",
         childrenElm:{
                   parentID:0,
                   myName:"john",
                   aihao:{
                            web:"html",
                             code:"js"
                    }
          }
}我想通过一个方法  getAttrVal(attrName)  直接取得该属性的值
下面是刚才编写的，但是不能达到预期的效果,这写法会输出N次。
alert(getAttrVal("code"))function getAttrVay(attrName)
{
var obj = a;
        for(var i in obj){
if(typeof(obj[i]) == "object" && obj[i] !== null){
getAttrVay(obj[i],attrName)
}else{
if (i == attrName){
return obj[i];
break;
}
}
}
}

解决方案 »

  1.   

    for(var i in obj) {
        alert(i);
    }
      

  2.   

    我上面只写了测试语句而已，我最终想要的不是alert,而是能引用的
    如 var mycode = getAttrVal("code")
      

  3.   

    a = {
             name:"text",
             childrenElm:{
                       parentID:0,
                       myName:"john",
                       aihao:{
                                web:"html",
                                 code:"js"
                        }
              }
    }alert(getAttrVay(a, "code"))
     
    function getAttrVay(obj, attrName)
    {
       for(var i in obj){
         if(typeof(obj[i]) == "object" && obj[i] !== null){                
           return getAttrVay(obj[i],attrName)                
         }else{
           if (i == attrName){                
             return obj[i];                
           }    
         }    
      }
    }
      

  4.   

    为什么我换了个对象就不行了呢
    function Assessment(){
    this.sex = null;
    this.married = null;
    this.age = 20;
    this.address = {
    provinces:0,
    city:0
    };
    this.houseState = null;
    this.houseCosts = null;
    this.familyStructure = {
    toddlers:0,
    elementary:0,
    teenager:0,
    movedOut:0,
    movedBackIn:0
    };
    this.familyCost = null;
    this.payForEducation = null;
    this.loans = {
    factors:{
    auto:0,
    personal:0,
    education:0,
    otherA:0
    },
    attachedFactors:{
    charities:0,
    special:0,
    elders:0,
    otherB:0
    },
    lowerFactionrs:{
    cash:0,
    savings:0,
    insurance:0,
    otherC:0
    }
    } 
    }
    function getAttrVay(obj, attrName)
    {
       for(var i in obj){
         if(typeof(obj[i]) == "object" && obj[i] !== null){                
           return getAttrVay(obj[i],attrName)                
         }else{
           if (i == attrName){                
             return obj[i];                
           }    
         }    
      }
    }
    var a = new Assessment();
    alert(getAttrVay(a, "auto"))
      

  5.   


    <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
    <html xmlns="http://www.w3.org/1999/xhtml">
    <head>
    <title> new document </title>
    <style type="text/css">
    #aa {}
    </style>
    </head><body>
    <script type="text/javascript"> function Assessment(){
    this.sex = null;
    this.married = null;
    this.age = 20;
    this.address = {
    provinces:0,
    city:0
    };
    this.houseState = null;
    this.houseCosts = null;
    this.familyStructure = {
    toddlers:0,
    elementary:0,
    teenager:0,
    movedOut:0,
    movedBackIn:0
    };
    this.familyCost = null;
    this.payForEducation = null;
    this.loans = {
    factors:{
    auto:0,
    personal:0,
    education:0,
    otherA:0
    },
    attachedFactors:{
    charities:0,
    special:0,
    elders:0,
    otherB:0
    },
    lowerFactionrs:{
    cash:0,
    savings:0,
    insurance:0,
    otherC:0
    }
    } 
    }
    function getAttrVay(obj, attrName)
    {
       for(var i in obj){
         if(obj[i] instanceof Object){                
           var s = getAttrVay(obj[i],attrName);
           if(s!==undefined) return s;
         }else{
           if (i == attrName){
             return obj[i];                
           }    
         }    
      }
    }
    var a = new Assessment();
    alert(getAttrVay(a, "auto"))