Last Updated on February 6, 2024 by Mathew Diekhake

A computer script is a string of code that can be interpreted and carried out by another program. An example of a programming script is JavaScript. JavaScript is core to the internet and allows developers to use scripting language to update content, control media, and animate images, and helps many features you see on websites function.

This page displays common known parasites that we may have identified on websites. Common known parasites may be false positives or real parasites.

A computer parasite is illicit content on a webpage that is often disguised, hidden, or invisible such as spam links, iframes, malicious scripts, and redirects.

Minified Javascript:

It is common to find minified javascipt show as a suspicious inline script. You can see javascipt in the script where it says “js.”

(function(){var js = "window['__CF$cv$params']=

We see many instances of this parasite. Here is a full example:

(function(){var js = "window['__CF$cv$params']={r:'80afbc532c07025e',t:'MTY5NTQ0MDEwNi42MDIwMDA='};_cpo=document.createEl...

This script is minified javascript being converted to old javascript for backward compatibility. Other examples on Reddit.

Set Timeout Function:

A common false positive for suspicious inline scripts is scripts with a set timeout function such as:

setTimeout(function(){{var s=document.createElement

Example:

setTimeout(function(){{var s=document.createElement('script');s.type='text/javascript';s.charset='UTF-8';s.src=((location...

Similar scripts that include a set timeout function can be found on Stack Overflow.

Load/Unload JavaScript:

You may find loading and unloading of JavaScript show up as a false positive for suspicious inline scripts.

Example:

(function () {let loadjscssfile = function (filename, filetype, success) {let fileref = null;if (filetype ==="js") {filer...

Similar scripts for loading and unloading JavaScript found on Stack Overflow.

Set USERHEAT Tag:

Set USERHEAT tag in JavaScript can show up as a false positive in inline scripts.

Example:

(function(add, cla){window['UserHeatTag']=cla;window[cla]=window[cla]||function(){(window[cla].q=window[cla].q||[]).push(...

Similar scripts for set USERHEAT tag in JavaScript found on GitHub.