Question

I am wondering what this technique is called and what it does. It seems to be validating some regular expression on the variable url. I am customizing another persons code:

var url = document.getElementById("editorURL").value;   
if(/(file|http).*/.test(url)) {

}

Maybe someone has a link to an article that explains this a bit more in-depth?

Answer 1

This is a regular expression checking whether url begins with either file or http, an effort to make sure the value entered is a proper URL pointing to a resource that can be opened in a browser.

Seeing as it fails to check for the subsequent :// part (and would for example match filexyz or httphttphttp), I would say it is not perfect.

More on the test() method at W3Schools.

The test() method tests for a match in a string.

This method returns true if it finds a match, otherwise it returns false.