Check if Javascript script exists on page

Question

I have a bookmarklet that I\'ve made and it loads a script from my server onto the users current page. However I have an if check in my script that if a condition is not met the

Answer 1

Just check the selector length. Here's an example using jQuery:

if ($('script[src="http://xxx.co.uk/xxx/script.js"]').length > 0) {
    //script exists
}