Execute SQL query from javascript

Alright lads,

First of all, if this has already been throughly answered somewhere else, I apologise, I did do a search for this issue but haven't found much helpful info (that I can understand at least).

MY ISSUE

Basically, what I'm trying to do is something like this in javascript:

if (x>y) {
update sql database with x;
}

I feel like such a fool typing that out, it seems so simple but I just can't find a way to get it to work nicely. I understand the JavaScript is client side and sql is server side yadah-yadah-yadah but there MUST be a simple way to get them to interface right?

Again, I apologise if this is a really stupid question or I am overlooking a really simple answer somewhere else, but this is for a project I'm working on that needs to be finished soon, so I am running out of time and coming here for a last ditch effort at finding a solution to my problem.

Thanks for reading this far at least, God bless,

Chris.