Ways to call a Javascript function using the value of a string variable? [duplicate]

Answer 1

Looks fine to me. I would probably create a simple helper function like following:

function runFunction(name, arguments)
{
    var fn = window[name];
    if(typeof fn !== 'function')
        return;

    fn.apply(window, arguments);
}

//If you have following function

function foo(msg)
{
    alert(msg);
}

//You can call it like

runFunction('foo', ['test']); //alerts test.

Answer 2

I have created a function to call a named function. It works both in browser and in Node.js. I have created a gist (https://gist.github.com/netsi1964/3f19bd96f2d6e18bd818) which also contains a small test. The fingerprint of the function is: callFunction(scope, fn, args). It sets the scope in the function to the specified scope, and defaults to window (in browser) and global (in Node.js). To answer your original request you would use it like this: callFunction(window, "foo",["test"])

Answer 3

I personally wouldn't bother even with a helper function

  window[someKey]('test')

would be fine.

However I wouldn't general maintain a set of possible functions to call at the global scope anyway. Hence I would use a more general pattern:-

 obj[someKey]('test')

where obj may be this, a property of this or variable from a closure.

Answer 4

You can use eval(str)

eval('foo();');

use this with extreme caution.

Answer 5

You can simply use it like this... (of course substitute the strings with variables where needed)

document["getElementById"]("elementName")["style"]["border"] = "1PX SOLID GREEN";

Which is also easily/usually typed like this of course...

document.getElementById("elementName").style.border = "1PX SOLID GREEN";

Here's another multi-dimensional example...

var myObject = new Object();
myObject["myValue"]["one"] = "first value";
myObject["myValue"]["two"] = "second value";
alert(myObject["myValue"]["two"]); //outputs "second value"

Which could also be written as...

var myObject = new Object();
myObject["myValue"] = {one: "first value", two: "second value"};
alert(myObject["myValue"]["two"]); //outputs "second value"