Javascript Resizable Container

Resizable Contianer Script

var responsive = document.querySelector('.responsive');
var resize = document.querySelector('.resize');
var content = document.querySelector('.content');

var mousedown = false;
var locX = 0;
var locY = 0;
var side = "";

resize.addEventListener('mousedown', function(event){
   mousedown = true;
   getSide(event);
});

window.addEventListener('mouseup', function(event){
   mousedown = false;
   reset();
})

window.addEventListener('mousemove', function(event){
   if(!mousedown) return;
   event.preventDefault();
   if(locX == 0){
      locX = event.clientX;
      locY = event.clientY;
   }
   var diffX = event.clientX - locX;
   var diffY = event.clientY - locY;
   locX = event.clientX;
   locY = event.clientY;
   
   var oldWidth = Number(responsive.style.width.split('p')[0]) || 600;
   var oldHeight = Number(responsive.style.height.split('p')[0]) || 300;
      
   switch(side){
      case 'right':
         diffY = 0;
         break;    
      case 'left':
         diffY = 0; diffX = -diffX;
         break;
      case 'top':
         diffX = 0; diffY = 0;
         break;
      case 'bottom':
         diffX = 0;
         break;
   }
   responsive.style.width = (oldWidth + diffX*2) + 'px';
   responsive.style.height = (oldHeight + diffY) + 'px';
});

var reset = function(){
   locX = 0;
   locY = 0;
}

var getSide = function(event){
   var padding  = (resize.offsetWidth - content.offsetWidth)/2;

   var mx = event.clientX;
   var my = event.clientY + window.scrollY; 
   //Get Side Locations
   var outRight = responsive.offsetWidth + responsive.offsetLeft;
   var inRight = outRight - padding;
   var outLeft = responsive.offsetLeft;
   var inLeft = outLeft + padding;
   var outTop = responsive.offsetTop + window.scrollY;
   var inTop = outTop + padding;
   var outBottom = responsive.offsetTop + responsive.offsetHeight;
   var inBottom = outBottom - padding;
   console.log(outBottom, my);
   side = "right";
   if(mx > outLeft && mx < inLeft)
      side = "left";
   if(my > outTop && my < inTop)
      side = "top";
   if(my < outBottom && my > inBottom)
      side = "bottom";
}