I have been accustomed to Aptana Studio.

Installing Firefox and Firebug, I ran the script on Firefox Web Browser.

But the Firefox didn't detect an error in the following:

------------------

var s1;

if ( (s1 > 4 ){

alert('hahha');

}

What is the best and most precise method to debug Javascript without any failure.

I tried JSLint but it couldn't.