Javascript: Running a while loop with an if statement to randomly generate things with a clause

Ok, so my question is very specific. I'm attempting to randomly generate a game stage for a 2D platformer I'm making. I want the platforms to be a set distance apart and I want the number of platforms created to be configureable. I believe the best way to do this is with a while loop that has an if statement nested in it, I've attempted it but can't get it working. Here's what I've tried.

var numLedges = 10;
var lastLedge;
var xSpace = randomIntFromInterval(0, 600);
var ySpace = randomIntFromInterval(0, 400);
var currentLedgeX = xSpace;
var currentLedgeY = ySpace;
var lastLedgeX = -1000;
var lastLedgeY = -1000;
var i = 0;
var loopCount = 0;
var maxLoops = 100;

function randomIntFromInterval(min,max)
{
    return Math.floor(Math.random()*(max-min+1)+min);
}

function createLedges() {
        do {   // This is supposed to make sure the platforms are being created 100px away in any direction
                if (currentLedgeX > lastLedgeX + 100 || currentLedgeX <     lastLedgeX - 100 && currentLedgeY > lastLedgeY + 100 || currentLedgeY <     lastLedgeY - 100) {
// Creates a ledge using phaser that is roughly 40 x 40px
                    var currentLedge = stillLedge.create(currentLedgeX,     currentLedgeY, 'platform');
                    currentLedge.body.immovable = true;
                    lastLedgeX = currentLedgeX;
                    lastLedgeY = currentLedgeY;
                    i++;
                }
            loopCount++;
        } while (i != numLedges || loopCount < maxLoops)
}

This doesn't appear to loop or it turns into an infinite loop somewhat randomly. If someone can think of a better way of doing this or a way to make this work I'd appreciate it. I'm out of ideas and haven't been able to find anything useful on the subject.