Home/ Questions/Q 762581
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-14T16:25:00+00:00

I have the following JavaScript in my HTML page referencing an HTML form on

  • 0

I have the following JavaScript in my HTML page referencing an HTML form on the page:

<script type="text/javascript">
<!--

var myForm = document.myForm;

function validateForm() {
    if (myForm.myInput == "")
        alert("Please input some text.");

        return false;
    }

    myForm.submit();
}

function showFormInput() {
    myForm.reset();

    document.getElementById('myInput').style.display = 'inline';
}

//-->
</script>

...

<form name="myForm" id="myForm" action="..." method="post">
    <input id="myInput" name="myInput" type="text" value="" style="display:none;" />
</form>

Both functions are throwing an exception when trying to access the variable myForm, saying that “myForm is null or not an object”. Why is this occurring?

UPDATE: One thing I think I’m gathering from this is that global variables should generally be used for string literals – not elements in the DOM. I”m going to go forward with this, and use element variables sparingly, and only after the DOM has been loaded.

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    What browser are you using?

    IN general you should never use document.* access. This is an MS-IE convention. Instead, use

    var myForm = document.getElementById( 'myForm' ) ;
var myInput = document.getElementById( 'myInput' ) ;

if( myInput.value == '' )
{
    // its empty!
}

    As outis noted, either put your script block at the bottom of your page, or use the onload event of <body> tag, like this

    <script>
function go()
{
    alert( "The DOM has been assembled and can be accessed.. nOW!!!" ) ;
    var myForm = document.getElementById( 'myForm' ) ; // ...
}
</script>
<body onload="go() ;">
</body>
    • 0