JavaScript Demo01

判断用户是不是输入用户名以及密码-

  1. <!DOCTYPE html>  
  2. <!--在页面中添加用户登陆表单以及表单元素-->  
  3. <html>  
  4.     <head>  
  5.         <meta charset="utf-8">  
  6.         <title>demo01</title>  
  7.     </head>  
  8.     <body>  
  9.         <form name="form1" method="post" action="">  
  10.             <!--action表示向何处发送数据-->  
  11.             <table width="221" border="1" cellspacing="0"   
  12.             bordercolor="#FFFFFF" bordercolordark="#CCCCCC"   
  13.             bordercolorlight="#FFFFFF">  
  14.             <!-- width 宽度  
  15.                 border 边框宽度  
  16.                 cellspacing 指定格线与格线之间的距离  
  17.                 borderColor 属性设置元素周围边框的颜色  
  18.                 bordercolordark 边框的暗色调  
  19.                 bordercolorlight 边框颜色亮度  
  20.                 colspan 属性规定单元格可横跨的列数   
  21.                 bgcolor 属性规定文档的背景颜色  
  22.                 align 位置 left靠左,center居中,right靠右  
  23.                 value 文本框的初始值-->  
  24.                 <tr>  
  25.                     <td height="30" colspan="2" bgcolor="aquamarine">.用户登录</td>  
  26.                 </tr>  
  27.                 <tr>  
  28.                     <td width="59" height="30">用户名:</td>  
  29.                     <td width="162"><input name="user" type="text" id="user"></td>  
  30.                 </tr>  
  31.                 <tr>  
  32.                     <td height="30">密码</td>  
  33.                     <td><input name="pwd" type="text" id="pwd"></td>  
  34.                 </tr>  
  35.                 <tr>  
  36.                     <td height="30" colspan="2" align="center">  
  37.                         <input name="Button" type="button" class="btn_grey" value="登陆" onclick="check()"/>  
  38.                              
  39.                         <input name="Submit2" type="reset" class="btn_grey" value="重置" />  
  40.                     </td>  
  41.                 </tr>  
  42.             </table>  
  43.         </form>  
  44.         <script language="JavaScript">  
  45.             //创建js方法  
  46.             function check(){  
  47.                 //获取用户名  
  48.                 var name=form1.user.value;  
  49.                 var pwd=form1.pwd.value;  
  50.                 if((name == "")||(name==null)){  
  51.                     alert("请输入用户名")  
  52.                     form1.user.focus();//赋予文本框焦点  
  53.                     return;  
  54.                 }else if((pwd=="")||(pwd==null)){  
  55.                     alert("请输入密码");  
  56.                     form1.pwd.focus();//密码框获取焦点  
  57.                     return;  
  58.                 }else{  
  59.                     form1.submit();//提交表单  
  60.                 }  
  61.             }  
  62.                 
  63.         </script>  
  64.     </body>  
  65. </html>  

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转载自www.cnblogs.com/songdongdong6/p/10061924.html