注册判断两次输入的密码是否一致

  <script type="text/javascript">
    function formCheck(){
       var pwd1 = document.getElementById("pwd1").value;
       var pwd2 = document.getElementById("pwd2").value;
       if(pwd1!=pwd2){
       alert("两次输入的密码不一致！");
       return false;
       }
       return true;
    }

    </script>

//required是HTML5的新属性，要求input提交表单时不能为空

<form method="post" action="#" onsubmit= "return formCheck() ">
        <input type="text" required="required" placeholder="username" name="username"></input>  
        <input type="password" id="pwd1" required="required" placeholder="password" name="password"></input>
        <input type="password" id="pwd2" required="required" placeholder="confirm password" name="passwordconfirm"></input>  
        <button class="but" type="submit">注册</button>
        </form>