<script type="text/javascript">
var obj = { a: 1, fn: function(){ }, c:{ d: 5 } }; console.log(obj.hasOwnProperty('a'));//true console.log(obj.hasOwnProperty('fn'));//true console.log(obj.hasOwnProperty('c'));//true console.log(obj.c.hasOwnProperty('d'));//true console.log(obj.hasOwnProperty('d'));//false, obj对象没有d属性 var str = new String(); console.log(str.hasOwnProperty('substring'));//false console.log(String.prototype.hasOwnProperty('substring'));//true </script>