4.return 返回值

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<html xmlns="http://www.w3.org/1999/xhtml">
<head>
  <title> return 返回值 </title>
  <meta http-equiv = "content-type" content ="text/html;charset=utf-8" />  
 </head> 

 <body>
  <script text="type/javascript">
    
    function sum(iNum1, iNum2) {
        return iNum1 + iNum2;
        alert(iNum1 + iNum2);
    }
    //sum(1,3);//不会执行alert语句

    //函数中可能有多个 return 语句 
    //例如，返回两个整数的差值
    function diff(iNum1, iNum2) {  
      if (iNum1 > iNum2) {
        return iNum1 - iNum2;
      } else {
        return iNum2 - iNum1;
      }
    }
    //diff(33,21) 
    //diff(21,33) 
  </script>
 </body>
</html>