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JavaScript

Posted by onurtekin
onurtekin
7,346 Points

Uncaught TypeError: undefined is not a function (WP Admin)

Hi,

i'm writing a plugin for wordpress. It creates a new post type. I have a js file which is embedded in with wp_enqueue_script method.

I'm trying to read the post_title text input, count the words. I'm stuck in this error:

Uncaught TypeError: undefined is not a function get_word_count (anonymous function)

I have nothing but the following, in my js file:

//Getting the number of words in 'title' field to send as a custom_field.

function get_word_count(){
    a = document.getElementByName("post_title").value;
    document.getElementById("kelime_sayisiw").value = a.split(" ").length;
};

document.getElementsByName("post_title").onkeyup = get_word_count();

any suggestions on getting rid of this error?

4 Answers

Aaron Graham
Aaron Graham
18,033 Points
Aaron Graham
Aaron Graham
18,033 Points

The type error is probably coming from this line:

a = document.getElementByName("post_title").value;

Element should be plural: .getElementsByName()

onurtekin
onurtekin
7,346 Points
onurtekin
onurtekin
7,346 Points

oh, that tiny letter. Thank you :)

here i have another one:

function get_word_count(){
    window.alert (document.getElementById("title").value);
};

window.alert (document.getElementById("title").value);

get_word_count, triggered by a button, gives me the correct alert, , but the last line tells me that it can not read the 'title'. "Cannot read property 'value' of null"

Am i missing a tiny thing again?

Aaron Graham
Aaron Graham
18,033 Points
Aaron Graham
Aaron Graham
18,033 Points

I am going to guess that you are loading this script before the DOM is loaded. If you are loading your script in <head> or at the top of <body>, this can happen. The easiest thing to try would be to just move your <script> to just before the closing </body>. See if that works.

onurtekin
onurtekin
7,346 Points
onurtekin
onurtekin
7,346 Points

Thank you again Aaron.

I have tried different things before your reply and managed it without changing the place of the script call.

//Getting the number of words in 'title' field to send as a custom_field.

function get_word_count(){
    b = document.getElementById("title").value;
    document.getElementById("kelime_sayisiw").value = b.split(" ").length;
};

window.onload = function() {
    get_word_count();
    var el = document.getElementById("title"); 
    el.addEventListener("keyup", get_word_count, false);
};
Aaron Graham
Aaron Graham
18,033 Points

I thought about mentioning window.onload, but it's my understanding that it might not be well supported among older browsers. Another option, and one that provides some backward compatability, is to use jQuery and the $(document).ready() function. It does basically the same thing as window.onload but has better support for old browsers. If supporting older browsers isn't something you care about, just forget I said any of this... Anyway, glad you got it working!

onurtekin
onurtekin
7,346 Points

Since this is a wp-admin page, and it records an important dat, wider browser support is important. I don't know about Jquery yet but i'll consider it definetly. Thank you.