[jquery] How do I add a simple jQuery script to WordPress?

I read the Codex and a few blog posts about using jQuery in WordPress, and its very frustrating. I've got as far as loading jQuery in functions.php file, but all of the guides out there are crappy because they assume you already have a ton of WordPress experience. For instance, they say that now that I'm loading jQuery through the functions.php file, now all I have to do is load my jQuery.

How exactly do I do this? What files, specifically, do I add code to? How exactly do I add it for a single WordPress page?

You can add jQuery or javascript in theme's function.php file. The code is as below :

add_action( 'wp_enqueue_scripts', 'add_my_script' );

function add_my_script() {
wp_enqueue_script(
    'your_script_name', // your script unique name 
    get_template_directory_uri().'/js/your-script.js', //script file location
    array('jquery') //lists the scripts upon which your script depends
);
}

For more detail visit this tutorial : http://www.codecanal.com/add-simple-jquery-script-wordpress/

If you use wordpress child theme for add scripts to your theme, you should change the get_template_directory_uri function to get_stylesheet_directory_uri, for example :

Parent Theme :

add_action( 'wp_enqueue_scripts', 'add_my_script' );
function add_my_script() {
    wp_register_script(
        'parent-theme-script', 
        get_template_directory_uri() . '/js/your-script.js', 
        array('jquery') 
    );

    wp_enqueue_script('parent-theme-script');
}

Child Theme :

add_action( 'wp_enqueue_scripts', 'add_my_script' );
function add_my_script() {
    wp_register_script(
       'child-theme-script', 
       get_stylesheet_directory_uri() . '/js/your-script.js', 
       array('jquery') 
    );

    wp_enqueue_script('child-theme-script');
}

get_template_directory_uri : /your-site/wp-content/themes/parent-theme

get_stylesheet_directory_uri : /your-site/wp-content/themes/child-theme

you can write your script in another file.And enqueue your file like this suppose your script name is image-ticker.js.

wp_enqueue_script( 'image-ticker-1', plugins_url('/js/image-ticker.js', __FILE__), array('jquery', 'image-ticker'), '1.0.0', true ); 

in the place of /js/image-ticker.js you should put your js file path.

There are many tutorials and answers here how to add your script to be included in the page. But what I couldn't find is how to structure that code so it will work properly. This is due the $ being not used in this form of JQuery.

So here is my code and you can use that as a template.

jQuery(document).ready(function( $ ){
  $("#btnCalculate").click(function () {
        var val1 = $(".visits").val();
        var val2 = $(".collection").val();
        var val3 = $(".percent").val();
        var val4 = $(".expired").val();
        var val5 = $(".payer").val();
        var val6 = $(".deductible").val(); 
        var result = val1 * (val3 / 100) * 10 * 0.25;
        var result2 = val1 * val2 * (val4 / 100) * 0.2;
        var result3 = val1 * val2 * (val5 / 100) * 0.2;
        var result4 = val1 * val2 * (val6 / 100) * 0.1;
        var val7 = $(".pverify").val();
        var result5 = result + result2 + result3 + result4 - val7;
        var result6 = result5 * 12;
        $("#result").val("$" + result);
        $("#result2").val("$" + result2);
        $("#result3").val("$" + result3);
        $("#result4").val("$" + result4);
        $("#result5").val("$" + result5);
        $("#result6").val("$" + result6);
  });
});

You can add custom javascript or jquery using this plugin.
https://wordpress.org/plugins/custom-javascript-editor/

When you use jQuery don't forget use jquery noconflict mode

As you mentioned, the simple way inside functions.php without using enqueue is this one:

add_action('wp_footer', 'customJsScript');
function customJsScript() {
  echo '
  <script>
  jQuery(function(){
    console.log("test");
  });
  </script>
  ';
}

As you see, you use the wp_footer action to inject the code.

But you may prefer to put directly the code inside header.php or footer.php if is a code that will be inserted all-over WordPress

The solutions I've seen are from the perspective of adding javascript features to a theme. However, the OP asked, specifically, "How exactly do I add it for a single WordPress page?" This sounds like it might be how I use javascript in my Wordpress blog, where individual posts may have different javascript-powered "widgets". For instance, a post might let the user change variables (sliders, checkboxes, text input fields), and plots or lists the results.

Starting from the JavaScript perspective:

1. Write your JavaScript functions in a separate “.js” file

Don’t even think about including significant JavaScript in your post’s html—create a JavaScript file, or files, with your code.

2. Interface your JavaScript with your post's html

If your JavaScript widget interacts with html controls and fields, you’ll need to understand how to query and set those elements from JavaScript, and also how to let UI elements call your JavaScript functions. Here are a couple of examples; first, from JavaScript:

var val = document.getElementById(“AM_Freq_A_3”).value;

And from html:

<input type="range" id="AM_Freq_A_3" class="freqSlider" min="0" max="1000" value="0" oninput='sliderChanged_AM_widget(this);'/>

3. Use jQuery to call your JavaScript widget’s initialization function

Add this to your .js file, using the name of your function that configures and draws your JavaScript widget when the page is ready for it:

jQuery(document).ready(function( $ ) {
    your_init_function();
});

4. In your post’s html code, load the scripts needed for your post

In the Wordpress code editor, I typically specify the scripts at the end of the post. For instance, I have a scripts folder in my main directory. Inside I have a utilities directory with common JavaScript that some of my posts may share—in this case some of my own math utility function and the flotr2 plotting library. I find it more convenient to group the post-specific JavaScript in another directory, with subdirectories based on date instead of using the media manager, for instance.

<script type="text/javascript" src="/scripts/utils/flotr2.min.js"></script>
<script type="text/javascript" src="/scripts/utils/math.min.js"></script>
<script type="text/javascript" src="/scripts/widgets/20161207/FreqRes.js"></script>

5. Enqueue jQuery

Wordpress registers jQuery, but it isn’t available unless you tell Wordpress you need it, by enqueuing it. If you don’t, the jQuery command will fail. Many sources tell you how to add this command to your functions.php, but assume you know some other important details.

First, it’s a bad idea to edit a theme—any future update of the theme will wipe out your changes. Make a child theme. Here’s how:

https://developer.wordpress.org/themes/advanced-topics/child-themes/

The child’s functions.php file does not override the parent theme’s file of the same name, it adds to it. The child-themes tutorial suggest how to enqueue the parent and child style.css file. We can simply add another line to that function to also enqueue jQuery. Here's my entire functions.php file for the child theme:

<?php
add_action( 'wp_enqueue_scripts', 'earlevel_scripts_enqueue' );
function earlevel_scripts_enqueue() {
    // styles
    $parent_style = 'parent-style';
    wp_enqueue_style( $parent_style, get_template_directory_uri() . '/style.css' );
    wp_enqueue_style( 'child-style',
        get_stylesheet_directory_uri() . '/style.css',
        array( $parent_style ),
        wp_get_theme()->get('Version')
    );

    // posts with js widgets need jquery
    wp_enqueue_script('jquery');
}

**#Method 1:**Try to put your jquery code in a separate js file.

Now register that script in functions.php file.

function add_my_script() {
    wp_enqueue_script(
      'custom-script', get_template_directory_uri() . '/js/your-script-name.js', 
        array('jquery') 
    );
}
add_action( 'wp_enqueue_scripts', 'add_my_script' );

Now you are done.

Registering script in functions has it benefits as it comes in <head> section when page loads thus it is a part of header.php always. So you don't have to repeat your code each time you write a new html content.

#Method 2: put the script code inside the page body under <script> tag. Then you don't have to register it in functions.

Beside putting the script in through functions you can "just" include a link ( a link rel tag that is) in the header, the footer, in any template, where ever. You just need to make sure the path is correct. I suggest using something like this (assuming you are in your theme's directory).

<script type="javascript" href="<?php echo get_template_directory_uri();?>/your-file.js"></script>

A good practice is to include this right before the closing body tag or at least just prior to your footer. You can also use php includes, or several other methods of pulling this file in.

<script type="javascript"><?php include('your-file.js');?></script>

Do you only need to load jquery?

1) Like the other guides say, register your script in your functions.php file like so:

// register scripts
if (!is_admin()) {
    // here is an example of loading a custom script in a /scripts/ folder in your theme:
    wp_register_script('sandbox.common', get_bloginfo('template_url').'/scripts/common.js', array('jquery'), '1.0', true);
    // enqueue these scripts everywhere
    wp_enqueue_script('jquery');
    wp_enqueue_script('sandbox.common');
}

2) Notice that we don't need to register jQuery because it's already in the core. Make sure wp_footer() is called in your footer.php and wp_head() is called in your header.php (this is where it will output the script tag), and jQuery will load on every page. When you enqueue jQuery with WordPress it will be in "no conflict" mode, so you have to use jQuery instead of $. You can deregister jQuery if you want and re-register your own by doing wp_deregister_script('jquery').

After much searching, I finally found something that works with the latest WordPress. Here are the steps to follow:

1. Find your theme's directory, create a folder in the directory for your custom js (custom_js in this example).
2. Put your custom jQuery in a .js file in this directory (jquery_test.js in this example).

3. Make sure your custom jQuery .js looks like this:

   (function($) {
   $(document).ready(function() {
   $('.your-class').addClass('do-my-bidding');
   })
   })(jQuery);
   

4. Go to the theme's directory, open up functions.php

5. Add some code near the top that looks like this:

   //this goes in functions.php near the top
   function my_scripts_method() {
   // register your script location, dependencies and version
      wp_register_script('custom_script',
      get_template_directory_uri() . '/custom_js/jquery_test.js',
      array('jquery'),
      '1.0' );
    // enqueue the script
     wp_enqueue_script('custom_script');
     }
   add_action('wp_enqueue_scripts', 'my_scripts_method');
   

6. Check out your site to make sure it works!

function xyz_scripts() {
    wp_enqueue_script('jquery');
}
add_action('wp_enqueue_scripts', 'xyz_scripts');

"We have Google" cit. For properly use script inside wordpress just add hosted libraries. Like Google

After selected library that you need link it before your custom script: exmpl

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.0/jquery.min.js"></script>

and after your own script

<script type="text/javascript">
    $(document).ready(function () {
        $('.text_container').addClass("hidden");
    });
</script>

In WordPress, the correct way to include the scripts in your website is by using the following functions.

wp_register_script( $handle, $src )
wp_enqueue_script( $handle, $src )

These functions are called inside the hook wp_enqueue_script.

For more details and examples, you can check Adding JS files in Wordpress using wp_register_script & wp_enqueue_script

Example:

function webolute_theme_scripts() {
    wp_register_script( 'script-name', get_template_directory_uri() . '/js/example.js', array('jquery'), '1.0.0', true );
    wp_enqueue_script( 'script-name' );
}
add_action( 'wp_enqueue_scripts', 'webolute_theme_scripts' );

Answer from here: https://premium.wpmudev.org/blog/adding-jquery-scripts-wordpress/

Despite the fact WordPress has been around for a while, and the method of adding scripts to themes and plugins has been the same for years, there is still some confusion around how exactly you’re supposed to add scripts. So let’s clear it up.

Since jQuery is still the most commonly used Javascript framework, let’s take a look at how you can add a simple script to your theme or plugin.

jQuery’s Compatibility Mode

Before we start attaching scripts to WordPress, let’s look at jQuery’s compatibility mode. WordPress comes pre-packaged with a copy of jQuery, which you should use with your code. When WordPress’ jQuery is loaded, it uses compatibility mode, which is a mechanism for avoiding conflicts with other language libraries.

What this boils down to is that you can’t use the dollar sign directly as you would in other projects. When writing jQuery for WordPress you need to use jQuery instead. Take a look at the code below to see what I mean:

Beside putting the script in through functions you can "just" include a link ( a link rel tag that is) in the header, the footer, in any template, where ever.

No. You should never just add a link to an external script like this in WordPress. Enqueuing them through the functions.php file ensures that scripts are loaded in the correct order.

Failure to enqueue them may result in your script not working, although it is written correctly.

You can use WordPress predefined function to add script file to WordPress plugin.

wp_enqueue_script( 'script', plugins_url('js/demo_script.js', __FILE__), array('jquery'));

Look at the post which helps you to understand that how easily you can implement jQuery and CSS in WordPress plugin.