platform-a.js

function colCheck(a,b) {
  var acx = a.w/2 + a.x,
  acy = a.h/2 + a.y,
  bcx = b.w/2 + b.x,
  bcy = b.h/2 + b.y;

  var w = (a.w + b.w)/2,
  h = (a.h + b.h)/2,
  dx = (acx - bcx),
  dy = (acy - bcy);

  if (a.w >= b.w) {
    return 'yes';
  } else {
    return 'not';
  }

}

var obja = {x:0,y:0,w:20,h:30},
objb = {x:20,y:38,w:20,y:20};