The above alert will only show is JavaScript is disabled in the browser.
Code courtesy of enable-javascript.com
Nowadays almost all web pages contain JavaScript, a scripting programming language that runs on visitor's web browser. It makes web pages functional for specific purposes and if disabled for some reason, the content or the functionality of the web page can be limited or unavailable. Here you can find instructions on how to enable (activate) JavaScript in five most commonly used browsers.
* Remember to uncomment the noscript tags for live use.