javascript - 如何使用单按钮单击更改占位符并在同一按钮单击事件上捕获新数据

<div id="abc" class="first">
           <input type="text" placeholder="Number" id="no" class="contact">
           <input type="text" placeholder="Pass"  id="pass" class="password">
 <div class="btn1" role="group">
         <button type="button" onclick="change()" class="btnregi">Register
        </button>
  </div>

    ----------
    javascript function
    var entry=0;
    function change()
        {

         if(entry==0)
      {
       document.getElementById("no").placeholder = "Enter user name...";
       document.getElementById("pass").placeholder = "Enter user password";
       entry++;
      }
       else
       {
          var newuser=document.getelementById("no").value;
          var newpass=document.getelementById("pass").value;
          alert("you entered new username"+newuser);
          alert("you entered new password"+newpass);
       }

我想更改占位符值onclick事件，并再次使用相同的按钮单击和方法来获取输入数据。我附上了我的代码，但无法正常工作。

最佳答案

您在这两行中误拼了getElementById。除此之外，代码对我来说似乎还不错。

var newuser = document.getElementById("no").value;
var newpass = document.getElementById("pass").value;

var entry = 0;

function change() {

  if (entry == 0) {
    document.getElementById("no").placeholder = "Enter user name...";
    document.getElementById("pass").placeholder = "Enter user password";
    entry++;
  } else {
    var newuser = document.getElementById("no").value;
    var newpass = document.getElementById("pass").value;
    alert("you entered new username: " + newuser);
    alert("you entered new password: " + newpass);
  }
}

<div id="abc" class="first">
<input type="text" placeholder="Number" id="no" class="contact">
<input type="text" placeholder="Pass" id="pass" class="password">
<div class="btn1" role="group">
  <button type="button" onclick="change()" class="btnregi">Register
        </button>
</div>