A for loop without any {}

Question

So I was reading about shuffling an array. And then I came across this script:

shuffle = function(o){ //v1.0
    for(var j, x, i = o.length; i; j = parseInt(         


        

Answer 1

If it's all on one line, no brackets are necessary. A lot of times in that third section inside the parenthesis, you just see i++, or something like that. Really, you can do many different things there. If you are able to pack everything in that third section, you don't even need a body for the for loop.

for (first section; second section; third section);

First section

Variables are declared and initialized. These variables are contained by the scope of the loop.

Second section

This is the condition checked with each pass of the loop.

Third section

Code that runs after each pass through the loop. It can be as simple as incrementing a variable, and as complex as... well, anything you can fit on the line, as long as syntax is correct.