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I looked and didn't find the case I have here -- a lot of the prior answers said 'wait for the 'onload' to call getElementById' but that's what I started with and it doesn't work -- getElementById returns null in this code in my index.php file:

<html>
<script type="text/javascript">

    function checkPwd()
    {
        var thePwd = document.getElementById("theUsersPassword");
        alert("the var thePwd is: " + thePwd);

    }
</script>        
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>Beta:</title>
</head>

<body onload="checkPwd()">

  <form method="post"  action="index.php">
    Beta: <input name="theUsersPassword" type="password"><br/>
    <input type="submit" value="Submit" />  
    </form>

</body>
</html>

I looked and didn't find the case I have here -- a lot of the prior answers said 'wait for the 'onload' to call getElementById' but that's what I started with and it doesn't work -- getElementById returns null in this code in my index.php file:

<html>
<script type="text/javascript">

    function checkPwd()
    {
        var thePwd = document.getElementById("theUsersPassword");
        alert("the var thePwd is: " + thePwd);

    }
</script>        
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>Beta:</title>
</head>

<body onload="checkPwd()">

  <form method="post"  action="index.php">
    Beta: <input name="theUsersPassword" type="password"><br/>
    <input type="submit" value="Submit" />  
    </form>

</body>
</html>
  • javascript
  • html
Share Improve this question asked Nov 22, 2011 at 19:07 wantTheBestwantTheBest 1,7204 gold badges46 silver badges71 bronze badges 2
  • 3 Alert statement should be alert("the var thePwd is: " + thePwd.value); – fardjad Commented Nov 22, 2011 at 19:10
  • okay now thePwd is HTMLInputElement but alert("The password's value entered was " + thePwd.value) and alert("The password's innerHTML entered was " + thePwd.innerHTML) are both empty after I type 'foo' in the password field -- is my form's post wiping out the contents somehow? – wantTheBest Commented Nov 22, 2011 at 19:29
Add a ment  | 

3 Answers 3

Reset to default 6

getElementById get an element by ID not by name. You must change 

<input name="theUsersPassword" type="password">

to

<input name="theUsersPassword" id="theUsersPassword" type="password" />

You are mixing up name and id

Edit:

In other words, you need to change

<input name="theUsersPassword" type="password">

to 

<input name="theUsersPassword" id="theUsersPassword" type="password">

You can use the code below. getElementById returned an object not a value.

JavaScript

function checkPwd()
{
    var thePwd = document.getElementById("theUsersPassword").value;
    alert("the var thePwd is: " + thePwd);

}

Html

<input name="theUsersPassword"  id="theUsersPassword"  type="password">

I looked and didn't find the case I have here -- a lot of the prior answers said 'wait for the 'onload' to call getElementById' but that's what I started with and it doesn't work -- getElementById returns null in this code in my index.php file:

<html>
<script type="text/javascript">

    function checkPwd()
    {
        var thePwd = document.getElementById("theUsersPassword");
        alert("the var thePwd is: " + thePwd);

    }
</script>        
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>Beta:</title>
</head>

<body onload="checkPwd()">

  <form method="post"  action="index.php">
    Beta: <input name="theUsersPassword" type="password"><br/>
    <input type="submit" value="Submit" />  
    </form>

</body>
</html>

I looked and didn't find the case I have here -- a lot of the prior answers said 'wait for the 'onload' to call getElementById' but that's what I started with and it doesn't work -- getElementById returns null in this code in my index.php file:

<html>
<script type="text/javascript">

    function checkPwd()
    {
        var thePwd = document.getElementById("theUsersPassword");
        alert("the var thePwd is: " + thePwd);

    }
</script>        
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>Beta:</title>
</head>

<body onload="checkPwd()">

  <form method="post"  action="index.php">
    Beta: <input name="theUsersPassword" type="password"><br/>
    <input type="submit" value="Submit" />  
    </form>

</body>
</html>
  • javascript
  • html
Share Improve this question asked Nov 22, 2011 at 19:07 wantTheBestwantTheBest 1,7204 gold badges46 silver badges71 bronze badges 2
  • 3 Alert statement should be alert("the var thePwd is: " + thePwd.value); – fardjad Commented Nov 22, 2011 at 19:10
  • okay now thePwd is HTMLInputElement but alert("The password's value entered was " + thePwd.value) and alert("The password's innerHTML entered was " + thePwd.innerHTML) are both empty after I type 'foo' in the password field -- is my form's post wiping out the contents somehow? – wantTheBest Commented Nov 22, 2011 at 19:29
Add a ment  | 

3 Answers 3

Reset to default 6

getElementById get an element by ID not by name. You must change 

<input name="theUsersPassword" type="password">

to

<input name="theUsersPassword" id="theUsersPassword" type="password" />

You are mixing up name and id

Edit:

In other words, you need to change

<input name="theUsersPassword" type="password">

to 

<input name="theUsersPassword" id="theUsersPassword" type="password">

You can use the code below. getElementById returned an object not a value.

JavaScript

function checkPwd()
{
    var thePwd = document.getElementById("theUsersPassword").value;
    alert("the var thePwd is: " + thePwd);

}

Html

<input name="theUsersPassword"  id="theUsersPassword"  type="password">

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