[乱七八糟]验证JS

 function ValiKey( obj )
 {
  //字符输入验证
  if ( ( window.event.keyCode < 97 || window.event.keyCode > 122 ) &&
   ( window.event.keyCode < 48 || window.event.keyCode > 57 ) &&
   ( window.event.keyCode < 65 || window.event.keyCode > 90 ) )
  {
   window.alert( "Please input A-Z or a-z or 0-9 chars!" );
   window.event.returnValue = false;
   obj.focus();
  }
 }
 
 function ValiEmail( obj )
 {
  //邮件地址验证
  var strEmail = new String( obj.value );
  if ( ( strEmail.indexOf("@",0) == -1 || strEmail.indexOf(".",0) == -1 || strEmail.length < 5 ) )
  {
   window.alert( "E-mail address error!" );
   obj.focus();
   obj.select();
  }
 }

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调用:
  <input id="username" name="username" type="text" onkeypress="ValiKey(this);"/>
  <input id="password" name="password" type="password" onchange="ValiEmail(this);"/>