JavaScript

Guides and tutorials relating to JavaScript and jQuery.

Fix: Uncaught ReferenceError: $ is not defined

This is a guide on how to fix a common error that occurs whenever the JQuery library hasn’t been loaded properly.

Calculating the mean / average in JavaScript.

This is a tutorial on how to calculate the mean / average of a JavaScript array.

JavaScript: Detect user activity / inactivity.

This is a short guide on how to detect user activity or inactivity using JavaScript.

JavaScript: Capitalize the first letter of a string.

In this tutorial, we will show you how to capitalize the first letter of a string using JavaScript.

JavaScript: Add a CSS class to an element.

This is a tutorial on how to add a CSS class to a HTML element using JavaScript.

JavaScript: Add text to a canvas element.

This is a beginners tutorial on how to add text to a canvas element using JavaScript.

JQuery: Add a new row to a table.

This is a tutorial on how to add a new row to a table using the JQuery library.

JavaScript: Detect when checkbox is ticked / unticked.

This is a JavaScript tutorial on how to detect whenever a checkbox has been ticked or unticked.

Calculating the execution time of an AJAX request.

This is a short JavaScript tutorial on how to calculate the execution time of an AJAX request.

Comparing two dates in JavaScript.

This is a short and simple guide on how to compare two dates in JavaScript.

How to detect HTTPS with JavaScript.

In this tutorial, we are going to show you how to detect HTTPS / SSL using JavaScript.

How to refresh a page using JavaScript.

This is a short guide on how to reload / refresh a page using JavaScript.

Populate SELECT options with Ajax.

This is a JavaScript tutorial on how to populate a SELECT element’s options with an Ajax request.

jQuery: Simple $.each example.

This is a short jQuery tutorial on how to use the $.each function.

Check if HTML element exists using JavaScript.

In this guide, I will show you how to check if a given HTML element exists using JavaScript.

Microsoft Edge CORS bug.

The other day, I stumbled across a CORS-related bug in Microsoft Edge.

Get file input size using JQuery.

In this guide, I will be showing you how to get the size of a selected input file using JQuery.

Getting a random value from a JavaScript array.

This is a short tutorial on how to get a random value from a JavaScript array. To do this, we will have to generate a random index number that represents an element in the array.

Fix: Tainted canvases may not be exported.

The other day, I came across a frustrating CORS-related error while developing a Facebook Instant Game. This is a short post on how I fixed it.

JavaScript: Add image to canvas.

This is a short guide on how to add an image to a canvas element using JavaScript.

JavaScript: How to get the day of the week.

In this guide, we show you how to get the day of the week using JavaScript. We also provide you with a custom function that you can copy.

JavaScript: Check if object property exists.

This is a short JavaScript tutorial on how to check if a given object property exists.

Check if a variable is a JavaScript object.

This is a short guide on how to check if a variable or value if an object using JavaScript.

Tutorial: Change a DIV’s text using JQuery.

This is a short tutorial on how to change the text of a DIV element using the JavaScript JQuery library.

Printing out JSON with PHP.

In this beginner’s tutorial, I will show you how to print out JSON using PHP and specify the correct Content-Type header.

Fix: Unexpected token o in JSON.

A short guide that I wrote on fixing the dreaded “Unexpected token o in JSON” error.

Call a PHP function using JavaScript.

This is a common question amongst beginner developers. In this article, I clear up the confusion about it and offer an alternative solution.

Changing a select element option using JavaScript.

This is a short JavaScript tutorial on how to change the selected option of a select HTML element. In this post, I will show you how to do it with and without JQuery.

Load image as BLOB using JQuery.

A short tutorial on how to load images as BLOB data using the JQuery JavaScript library.

Send JavaScript object via Ajax to PHP script.

This is a short guide on how to send a JavaScript object to a PHP script using an Ajax request.

JSON.stringify returning empty string / object.

The other day, I came across an issue where the JSON.stringify method failed to convert one of my objects into a JSON string.

JavaScript Date: One week ago.

This is a short tutorial on how to create a JavaScript date that is “7 days ago” or “30 days ago”.

Handling Ajax errors with jQuery.

This is a tutorial on how to handle errors when making Ajax requests via the jQuery library.

Ajax poll request every 10 seconds.

This is a short tutorial on how to send an Ajax request every 10 seconds – something that is often referred to as polling.

PHP Fix: No ‘Access-Control-Allow-Origin’ header.

This is a short guide on how to fix Access-Control-Allow-Origin issues when you are sending Ajax requests.