<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=gb2312" /> <title>测试页面</title> <script type="text/javascript"> function checkform(){ //验证用户名 if($("username").value == ""){ $("n_msg").innerHTML ="用户名不可以为空"; $("username").select(); $("username").focus(); return false; }else{ if($("username").value.length < 6){ $("n_msg").innerHTML = "用户名必须大于6个字符"; $("username").select(); $("username").focus(); return false; } } //验证密码 if($("password").value == ""){ $("p_msg").innerHTML ="密码不可以为空"; $("password").select(); $("password").focus(); return false; }else{ if($("password").value.length < 10){ $("p_msg").innerHTML = "密码必须大于10个字符"; $("password").select(); $("password").focus(); return false; } } //.....（下面的可以以此类推） return true; } function $(id){ return document.getElementById(id); } </script> <style type="text/css"> body{ font:12px 宋体} .c_red{ color:#f00} </style> </head> <body> <table width="500" border="0" cellspacing="0" cellpadding="0"> <form method="post" onsubmit="return checkform()"> <tr> <td width="89">用户名</td> <td width="223"><input name="username" type="text" id="username" /></td> <td width="188" id="n_msg" class="c_red"></td> </tr> <tr> <td>密码</td> <td><input name="password" type="password" id="password" /></td> <td id="p_msg" class="c_red"></td> </tr> <tr> <td colspan="3"><input name="sub" type="submit" id="sub" value="提交" /></td> </tr> </form> </table> </body> </html> ===========================