maxLength is not a function

Question

I have a problem with an html page

here a simplified version of the page

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

            function maxLength()
            {
                console.log('maxLength');
            }

        </script>
    </head>
    <body>
        <input type"text" onblur="maxLength()">
    </body>
</html>

on onblur event I receive this error

Uncaught TypeError: maxLength is not a function

but if i call the function from console it works without errors and print 'maxLength'

Why?

The code you posted works fine. Instead of the "simplified" version, perhaps you can post something closer to the *actual* version. — Pointy, Oct 30 '18 at 18:28
My guess is that there's a global variable, property, or function called maxLength. Try a different name for your function. — j08691, Oct 30 '18 at 18:28
See [here](https://developer.mozilla.org/en-US/docs/Web/API/HTMLInputElement) in particular the `maxLength` property — Matt Burland, Oct 30 '18 at 18:35

alex · Accepted Answer · 2018-10-30T18:33:10.693

4

The code there runs in the context of the input, which has defined maxLength.

Better developer tools would make it clearer:

maxLength is not a function at HTMLInputElement.onblur

Rename your function to something else or use a different way of attaching the event listener.

edited Oct 30 '18 at 18:33

answered Oct 30 '18 at 18:29

alex

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adityap · Answer 2 · 2018-10-30T18:45:08.117

0

If you rename the function to something else it should work fine for you. The explanation is aptly given with Alex already. Example:

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

            function maximumLength()
            {
                console.log('maxLength');
            }

        </script>
    </head>
    <body>
        <input type"text" onblur="maximumLength()">
    </body>
</html>

edited Oct 30 '18 at 18:45

answered Oct 30 '18 at 18:32

adityap

329
1
10

2

It's not a *keyword*, it's a property of `HTMLInputElement` which is being looked up because `onEvent` type attributes are weird for historical reasons and backwards compatibility. – alex Oct 30 '18 at 18:34

maxLength is not a function

2 Answers2