Question

Is JavaScript intended to be running as little as possible on a website/webapp? By that I mean is the usual intention to run through all your js files as soon as the page loads and put them aside, and then when functions come up to execute them right away and be done with it?

I’m working on a project using google maps and I have a custom marker object scripted out, and a debugger has told me that the browser runs through all my js files before anything even appears on the page.

My problem comes in here: I wanted to animate certain markers to bounce up and down continuously with jQuery (similar to OS X icons in the dock) and my several attempts at infinite loop functions all just crash the browser. So I understand that the browser doesn’t like that, but is there a way to have a simple script be repeating itself in the background while the user navigates the page? Or is JavaScript just not supposed to be used that way?

(I worked with Flash for a long time so my mindset is still there.)

Answer 1

Yes, Javascript functions should just do their bit and exit as soon as possible. The GUI and the scripts run on the same single thread, so as long as you are inside a Javascript function, nothing shows up in the browser. If you try to use an infinite loop, the browser will appear to freeze.

You use the window.setInterval and window.setTimeout methods to trigger code that runs at a specific time. By running an interval that updates something several times a second, you can create an animation.