setTimeout() and setting parameters

While the marked correct answer is one method of achieving this... I don't believe it is the correct.

See the attached JS Fiddle:http://jsfiddle.net/PWHw3/

What we are doing here basically is:

setTimeout(function, timeout, param);

Example:

var test = function(a){    var b = (a) ? a : "fail";    alert(b);};setTimeout(test, 500, "works");

This works for me, and eliminates the needs to pass through two functions.

To make it work, and do it without using the nasty eval version of setTimeout change:

var t = setTimeout("HideMenu(someNum)", 200);

to this:

var t = setTimeout(function(s) {                   return function() { HideMenu(s) } }(someNum), 200);

This way you pass the value of someNum into the variable s in the scope of the setTimeout.

setTimeout accepts a function and a millisecond delay. The function can be either a function reference or a string that will get evaluated when the timeout fires. Your current sequence looks like this:

• mouseleave function

  • assign variable someNum a value. someNum is scoped tothe current function
  • set a timer to evaluate the string "HideNum(someNum)" after 200ms.
  • end function, leave function scope

• 200ms passes

• "HideNum(someNum)" is evaluated. It should throw an exception as the variable someNum is undefined. That's why HideNum is not being called - check for errors in your console.

What you want is a function reference, which will keep your someNum in scope (via closure - which you might want to read up on).

setTimeout(function() {   HideNum(someNum); }, 200);

You'll find the Mozilla docs a better reference for JavaScript. Here's the window.setTimeout docs.