Question

Possible Duplicate:
Variable scope in Javascript for loop

for(i=0;i<4;i++){

}

Do I need to say:

for(var i=0;i<4;i++) …?

Otherwise things will be global, right?

Answer 1

No, you don’t need to declare the iterator variable inside a loop. This is also perfectly valid –

var i;

for(i=0; i<4; i++)
    alert(i);

An example on jsfiddle.

You may also want to see this section about variable scope and this page about function scope on MDN.