How to call function using the value stored in a variable?

Question

I have a variable

var functionName="giveVote";

What I need to do is, I want to call function stored in var functionName. I tried using functionName(); . But its not working. Please help.

Edit Based on the same problem, I have

$(this).rules("add", {txtInf: "^[a-zA-Z'.\s]{1,40}$" }); 

rules is a predifined function which takes methodName:, here I have hardcoded txtInf. But I want to supply a javascript variable here, to make my code generic. var methodName="txtInf";

Here I want to evaluate methodName first before being used in rules function.

$(this).rules("add", {mehtodName: "^[a-zA-Z'.\s]{1,40}$" }); 

Answer 1

You have a handful of options - two basic ones include window[functionName]() or setTimeout(functionName, 0). Give those a shot.

Edit: if your variable is just the string name of a function, use those; otherwise, if you're able to actually assign a function reference to the variable (eg, var foo = function() {};), you could use the foo() notation, or foo.apply(this, []), etc.

Edit 2: To evaluate methodName in place prior to $(this).rules() firing, you'd just apply the first syntax above (using the window object), like so:

$(this).rules("add", {window[methodName](): ...});

I think that's what you're asking - if not, please clarify a bit more and I'll be happy to rewrite a solution.