Javascript function return src path

Question

I\'m trying to set an \'src\' by calling a javascript function that returns the path like so:

the fun

Answer 1

Building on Eugen's answer, I wanted something self-contained (no id's, as inline as possible) that would not require a hosted pixel.gif image. I came up with a few possibilities:

One option would be to use a base64 encoded src URL instead (as small as possible). Note that data-uris are supported in IE8+:

See it in action on jsfiddle.

A second option would be to use document.write to write the image tag directly with an inline script. Just put the below

See it in action on codepen.io.

A third (perhaps even more hackish) option would be to forcibly break the image by supplying a null src, and (ab)use the onerror callback.

This works in IE11 and Chrome, but not Firefox:

See it in action on jsfiddle.

This fourth option relies on a simple function that sets an tag followed immediately by an inline

And in your :

See it in action on codepen.io.

Summary: I'm just ideating. Each option has different implications and requirements -- they're all workarounds, and should be tested thoroughly for your specific use case. Personally I think the first option (base64 URI) is the most solid (if you ignore old IE browsers, which I happily can).