delete只能删除属性，不能删除变量
1 var a = "roboce"; 2 delete a; // false 3 a; 4 5 6 b = "haha"; 7 delete b; // true 8 b; // window.b;
javascript------>delete
原文：http://www.cnblogs.com/daishuguang/p/4007882.html
