1 < script LANGUAGE = " JavaScript " >
 2 function  checkvalue()
 3 {
 4    if (document.welcomeform.nickname.value == "" )
 5    {
 6    alert( " 昵称不能为空！ " );
 7     return ( false );
 8    }
 9    if (document.welcomeform.password.value == "" )
10    {
11    alert( " 密码不能为空！ " );
12     return ( false );    
13    }
14   document.welcomeform.submit(); 
15    return ( true );   
16 }
17 </ script >
18
19 < body >
20 < form name = " welcomeform "  method = " post "  action = " welcome.asp " >
21    < a href = " # "  onclick = " javascript:checkvalue();return false: " > 登录 </ a >
22 </ form >  
23 </ body >