AJAX

content-filter.php

add_filter( 'the_content', 'post_love_display', 99 );
function post_love_display( $content ) {
	$love_text = '';

	if ( is_single() ) {
		
		$love = get_post_meta( get_the_ID(), 'post_love', true );
		$love = ( empty( $love ) ) ? 0 : $love;

		$love_text = '<p class="love-received"><a class="love-button" href="#" data-id="' . get_the_ID() . '">give love</a><span id="love-count">' . $love . '</span></p>'; 
	
	}

	return $content . $love_text;

}

enqueue-first.php

add_action( 'wp_enqueue_scripts', 'ajax_test_enqueue_scripts' );
function ajax_test_enqueue_scripts() {
	wp_enqueue_script( 'test', plugins_url( '/test.js', __FILE__ ), array('jquery'), '1.0', true );
}

final-display.php

add_filter( 'the_content', 'post_love_display', 99 );
function post_love_display( $content ) {
	$love_text = '';

	if ( is_single() ) {
		
		$love = get_post_meta( get_the_ID(), 'post_love', true );
		$love = ( empty( $love ) ) ? 0 : $love;

		$love_text = '<p class="love-received"><a class="love-button" href="' . admin_url( 'admin-ajax.php?action=post_love_add_love&post_id=' . get_the_ID() ) . '" data-id="' . get_the_ID() . '">give love</a><span id="love-count">' . $love . '</span></p>'; 
	
	}

	return $content . $love_text;

}

final-js.js

jQuery( document ).on( 'click', '.love-button', function() {
	var post_id = jQuery(this).data('id');
	jQuery.ajax({
		url : postlove.ajax_url,
		type : 'post',
		data : {
			action : 'post_love_add_love',
			post_id : post_id
		},
		success : function( response ) {
			jQuery('#love-count').html( response );
		}
	});

	return false;
})

hooks.php

add_action( 'wp_ajax_nopriv_post_love_add_love', 'post_love_add_love' );
add_action( 'wp_ajax_post_love_add_love', 'post_love_add_love' );

function post_love_add_love() {
	
}

increment-final.php

function post_love_add_love() {
	$love = get_post_meta( $_REQUEST['post_id'], 'post_love', true );
	$love++;
	update_post_meta( $_REQUEST['post_id'], 'post_love', $love );
	if ( defined( 'DOING_AJAX' ) && DOING_AJAX ) { 
		echo $love;
		die();
	}
	else {
		wp_redirect( get_permalink( $_REQUEST['post_id'] ) );
		exit();
	}
}

js-first.js

jQuery(document).ready( function($) {

	$.ajax({
		url: "http://yourwebsite.com",
		success: function( data ) {
			alert( 'Your home page has ' + $(data).find('div').length + ' div elements.');
		}
	})

})

localize.php

add_action( 'wp_enqueue_scripts', 'ajax_test_enqueue_scripts' );
function ajax_test_enqueue_scripts() {
	if( is_single() ) {
		wp_enqueue_style( 'love', plugins_url( '/love.css', __FILE__ ) );
	}

	wp_enqueue_script( 'love', plugins_url( '/love.js', __FILE__ ), array('jquery'), '1.0', true );

	wp_localize_script( 'love', 'postlove', array(
		'ajax_url' => admin_url( 'admin-ajax.php' )
	));

}

love-basic-ajax.js

jQuery( document ).on( 'click', '.love-button', function() {
	var post_id = jQuery(this).data('id');
	jQuery.ajax({
		url : postlove.ajax_url,
		type : 'post',
		data : {
			action : 'post_love_add_love',
			post_id : post_id
		},
		success : function( response ) {
			alert(response)
		}
	});
})

plugin.php

<?php 

/**
 * Plugin Name: Ajax Test
 * Plugin URI: http://danielpataki.com
 * Description: This is a plugin that allows us to test Ajax functionality in WordPress
 * Version: 1.0.0
 * Author: Daniel Pataki
 * Author URI: http://danielpataki.com
 * License: GPL2
 */

post-love.js

jQuery( document ).on( 'click', '.love-button', function() {
	var post_id = jQuery(this).data('id');
	jQuery.ajax({
		url : postlove.ajax_url,
		type : 'post',
		data : {
			action : 'post_love_add_love',
			post_id : post_id
		},
		success : function( response ) {
			jQuery('#love-count').html( response );
		}
	});
})

post-love.php

add_action( 'wp_ajax_nopriv_post_love_add_love', 'post_love_add_love' );
add_action( 'wp_ajax_post_love_add_love', 'post_love_add_love' );

function post_love_add_love() {
	$love = get_post_meta( $_POST['post_id'], 'post_love', true );
	$love++;
	if ( defined( 'DOING_AJAX' ) && DOING_AJAX ) { 
		update_post_meta( $_POST['post_id'], 'post_love', $love );
		echo $love;
	}
	die();
}

style.css

.entry-content .love-button {
	background: #f14864;
	color: #fff;
	padding:11px 22px;
	display:inline-block;
	border:0px;
	text-decoration: none;
    box-shadow: 0px 6px #d2234c;
    position:relative;
}

.entry-content .love-button:hover{
	top:3px;
    box-shadow: 0px 3px #d2234c;
}

.entry-content .love-button:active{
	top:6px;
    box-shadow: none;
}


#love-count {
	background: #eee;
    box-shadow: 0px 6px #ddd;	
	color: #666;
	padding:11px 22px;
	display:inline-block;
}

style.php

add_action( 'wp_enqueue_scripts', 'post_love_assets' );
function post_love_assets() {
	if( is_single() ) {
		wp_enqueue_style( 'love', plugins_url( '/love.css', __FILE__ ) );
	}