Very useful Javascript feature that can prevent a user from losing the data they are entering in an entry field or text editor in case of unintentional leaving of a page.
You don't need Photoshop or some other advanced piece of software to resize a large number of images at once. You can use Microsoft Office Picture Manager which is part of the Office suite.
You will find out how to summarize cells that have a same color of the font, the red one in my case. Really useful when working with different types of specific data in Excel.
Often in PHP you want the same block of code to run over and over again and instead of adding several almost equal lines, you can use loops to perform this task much easier.
