Wanted to write my own form slider, Jquery/JS
Here are some suggestions to simplify the syntax:


For pos, use an array literal: var pos = [0, 67, 133, 199, 267, 333]

Similar thing for compare: var compare = [];

You're missing semi-colons after some statements
You can make initializing compare simpler using Array.prototype.map (doesn't work on IE &lt; 9):

var compare = pos.map(function (e) {
    return e - mouseMovement;
});



If you need to support IE &lt; 9, I'd either implement map, or do basically what you're doing, but use Array.prototype.push instead:

for(var c=0;c&lt;=5;c++){//do some math to make sure the slider ends up going to the closest interval postion
    compare.push(Math.abs(pos[c] - mouseMovement));
}


You've got a lot of undefined variables that will default to the global scope:


sliderPos- not used
mouseCoordStart- dangerous because it might not be defined when it's used
oncontextmenu- not used anywhere

333 in your mousemove handler is magic, perhaps it should be pos[pos.length-1]?


I'm not going to comment on jQuery plug-in style (I don't use jQuery) or your implementation of a "form slider" (which I assume is an implementation of an HTML5 input range).

Hopefully this was useful!