Question

Why when passing the code (surrounded by ”) like so:

setTimeout('alert("James Blunt is bad")', 5000);

Is there the 5 second pause before showing what we all know and when passing function reference like so:

setTimeout(alert("James Blunt is bad"), 5000);

There is no pause?

http://jsfiddle.net/eBcpc/

Answer 1

If your second example, you are not passing a function.

You are calling alert and passing its return value (and the return value of alert is not a function).

Function references don’t end in (…)

setTimeout(function () { alert("Hello, world"); }, 5000);

Or, with weaker browser support, pass the arguments to alert in an array as the third argument to setTimeout.:

setTimeout(alert, 5000, ["Hello, world"]);