js如何将对象属性key-value变成字符串输出

<script>
var asfman = {};
asfman.dict = {
    "keys": function(obj){
        var b = [];
        for(var i in obj){
          b.push(i);
        }
        return b;
      },
      "values": function(obj){
        var b = [];
        for(var i in obj){
          b.push(obj[i]);
        }
        return b;
      },
      "items": function(obj){
        var b = [];
        for(var i in obj){
          b.push([i, obj[i]]);
        }
        return b;
      }
};
var  item = {
       color    : "#cccccc",
       border  : "1px solid #ff0000",
       margin  : "0px",
       padding : "0px"

  }
alert(asfman.dict.items(item).join("\n"));
</script>