The title is probably a bit unclear, i’ll try to explain the question with an example.
At http://imgur.com there is an upload button for uploading images. When it is clicked, the url does not change. Instead, a pop-up appears, and it is triggered from javascript. Now, what if I wanted to give a link for the webpage that automatically opens the pop-up on default, without having the user click the upload button.
This is a bit tricky because the url for the homepage/upload page is the exact same, but one of them is a pop-up.
Thanks for the help!
In general, it is not possible to invoke a script on another website, and for good reason. Do some research into “cross site scripting” for an in depth explanation.
There is however, an Imgur API available to you if you want to hook into the website’s functionality.