Question

I have created a function that runs after 1.8 million milliseconds (I’m using 1.8 seconds for test purposes), but the timeout I’m using never seems to work – even though it’s exactly the same one I’ve used for every other web app/site I’ve made, ever.

Core code:

setTimeout(Test, 10);

var Test = function(){
    alert("KEMAH");
};

Jsfiddle: http://jsfiddle.net/zbMCC/1/

Answer 1

Place the timeout after the function expression.

var Test = function(){
    alert("KEMAH");
};
setTimeout(Test, 10);

Function expressions (functions assigned to variables) are not “hoisted-up” in the scope. Thus the code executes in the order they appear.

On the otherhand, function declarations are hoisted-up in the scope, so the following code runs perfectly. Notice how the function is declared. Its declared as a function with a name Test, instead of having a function assigned to the variable Test:

//because JavaScript treats function declarations as if they were declared
//UP HERE <--------------.
                       //|
setTimeout(Test, 10);  //|
                       //|
function Test(){ //------'
    alert("KEMAH");
};

JavaScript ses your code this way:

1. variable declarations
2. function declarations
3. variable assignments/operations (this is where everything else runs in the order they appear)