JS单词形式的运算符

1.void 运算表达式并忽略其返回值,比如void (1+2),void (0)

 1      <html>
 2 
 3         <head>
 4 
 5         <meta  http-equiv="content-type" charset="utf-8"/>
 6 
 7         <script type="text/javascript">
 8 
 9          alert(typeof(void(0)));  //void(0) 计算值为0,由于忽略返回值,typeof类型为:undefined
10 
11         </script>
12 
13         </head>
14 
15         <body>
16 
17         1.用onclick事件来灵活处理;2.void(expression)<br>
18 
19         <a href="javascript:void(0);" onclick="location.href='http://www.baidu.com';">百度</a>
20 
21         <a href="javascript:void(location.href='http://www.google.com')">谷歌</a>
22 
23         </body>
24 
25 </html>

  2.typeof 返回变量或值的类型,比如 typeof(void 1+2) ,typeof(void(1+2)) 

      由于运算符优先级,void 1+2 的运算过程为:

 

void(1+2)的计算过程为:

  3.new用于创建指定类的对象实列

  4.delete删除实列属性,对于delete有几点必须注意:

     1.只删除实列属性,而不会删除对象

 1 <html>
 2         <head>
 3         <meta  http-equiv="content-type" charset="utf-8"/>
 4         <script type="text/javascript">
 5          var parent={};
 6          var son={age:10};
 7          parent.son=son;
 8          alert(parent.son.age);//10
 9          delete parent.son;
10          alert(parent.son);//undefined
11          alert(son.age);//10
12         </script>
13         </head>
14         <body> 
15         </body>
16 </html>

 Ps:未完带补充....

 

 

原文地址:https://www.cnblogs.com/oxf5deb3/p/3698312.html