Calling a JavaScript function named in a variable

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Answer 1

I'd avoid eval.

To solve this problem, you should know these things about JavaScript.

1. Functions are first-class objects, so they can be properties of an object (in which case they are called methods) or even elements of arrays.
2. If you aren't choosing the object a function belongs to, it belongs to the global scope. In the browser, that means you're hanging it on the object named "window," which is where globals live.
3. Arrays and objects are intimately related. (Rumor is they might even be the result of incest!) You can often substitute using a dot . rather than square brackets [], or vice versa.

Your problem is a result of considering the dot manner of reference rather than the square bracket manner.

So, why not something like,

window["functionName"]();

That's assuming your function lives in the global space. If you've namespaced, then:

myNameSpace["functionName"]();

Avoid eval, and avoid passing a string in to setTimeout and setInterval. I write a lot of JS, and I NEVER need eval. "Needing" eval comes from not knowing the language deeply enough. You need to learn about scoping, context, and syntax. If you're ever stuck with an eval, just ask--you'll learn quickly.