javascript实现输入框输入内容不能重复
    <html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>无标题文档</title>
<script language="javascript" type="text/javascript">
function tt(){
           var psd1=document.getElementById("psd1").value;
           var psd2=document.getElementById("psd2").value;
           if(psd1=psd2){
          alert("输入框内容重复了!");
          return false;
    }
          return true;
        }
</script></head>
<body>
<form name="form1" onSubmit="tt()">
   输入框一:<input type="text" name="psd1" value="123456"/><br/>
   输入框二:<input type="text" name="psd2" value="123"/><br/>
   检查输入框:
   <input type="button" onclick="checkPass()" name="txt2"="检查"/>
 
<td><input type ="submit"></td>
</table>
</form></body>
</html>