判断数组里是不是包含某个值

判断数组里是否包含某个值？
我有一个数组，元素是对象，如何判断这个数组里任意一个对象包含有指定的属性？
比如

JScript code

[{"A":"a","B":"b"},{"A":"a","B":"b"},{"C":"c"}]

JScript code

    var arr = [{"A":"a","B":"b"},{"A":"a","B":"b"},{"C":"c"}] ;    for(var i=0;i<3;i++)    {        document.write(arr[i].A + '\n');    }
[解决办法]
JScript code
// 从数组中取出所有包含属性A的对象var array = [{ "A": "a", "B": "b" }, { "A": "a", "B": "b" }, { "C": "c"}];var result = $.grep(array, function (n, i) {    for (var key in n) {        if (key == "A") {            return true;        }        continue;    }});//result = [{ "A": "a", "B": "b" }, { "A": "a", "B": "b" }]
[解决办法]
JScript code
Array.prototype.isHas=function (value){    var max=this.length,res=false;    if(max==0){return false};    for(var i=0;i<max;i++){        for(var name in this[i]){            if(name==value){                res=true;                break;            }        };        if(res){break}    };    return res;};var arr = [{ "A": "a", "B": "b" }, { "C": "a", "D": "b" }, { "e": "c"}];var str=arr.isHas("A")?'存在':'不存在';alert(str)
[解决办法]
如果你的数组里面只是对象 比较容易
JScript code
var arrTest = [{"A":"a","B":"b"},{"A":"a","B":"b"},{"C":"c"}];    function isIncludeA(arrArr , sEqu){      if(arrArr instanceof Array){          var oObj = null;          var arrResult = new Array();          for(var i = 0; i < arrArr.length; i++){              oObj = arrArr[i];              if(oObj instanceof Object){                  for(var prop in oObj){                      if(oObj[prop] == sEqu){                          arrResult.push(oObj[prop]);                      }                  }              }          }          return arrResult.length == 0 ? "没有匹配项" : ("匹配项个数:" + arrResult.length);      }    }        window.onload = function(){        var result = isIncludeA(arrTest , "A");        alert(result);    };
[解决办法]
也没什么问题。只是写死了，结果返回不明确。思路是没有问题的

JScript code
Array.prototype.isHas=function (a){    if(this.length==0){return false};    for(var i=0;i<this.length;i++){        if(this[i][a]){return true}    }};var arr = [{ "A": "a", "B": "b" }, { "C": "a", "D": "b" }, { "e": "c"}];var str=arr.isHas("f")?'存在':'不存在';alert(str);
[解决办法]
判断对象数组里每个对象是否含有指定属性

   var arr = [{"theforever_csdn":"a","B":"b"},{"theforever_csdn":"a","B":"b"},{"碧海情天":"c"}] ;
   for(var i=0;i<arr.length;i++) 
 
   {
       document.write('第'+(i+1)+'个对象里'+(arr[i].theforever_csdn==undefined?'不含有':'含有') + '属性theforever_csdn<br/>');
   }