text: var initx;
  var inity;
  var newObjectMass = 1;
  var velDamp = 100;
  
  function onMouseUp(event) {
  
  	var xPrime = event.pageX;
  	var yPrime = event.pageY;
  	var newVel = new Vector((xPrime - initx) / velDamp, (yPrime - inity) / velDamp);
  
  	var newObj = new GravityObject(initx, inity, newObjectMass, newVel);
  
  	if(document.getElementById('fixed').checked) {
  
  		newObj.setFixed(true);
  		document.getElementById('fixed').checked = false;
  
  	}
  
  	objectList.push(newObj);
  
  }
  
  function onMouseDown(event) {
  
  	//event = canvas.relMouseCoords(event);
  
  	initx = event.pageX - 10;
  	inity = event.pageY - 10;
  
  	//objectList.push(new GravityObject(x,y,newObjectMass, new Vector(0,0)));
  
  }
  
  function relMouseCoords(event) {
  
  	var totalOffsetX = 0;
  	var totalOffsetY = 0;
  	var canvasX = 0;
  	var canvasY = 0;
  	var currentElement = this;
  
  	do{ 
  
  		totalOffsetX += currentElement.offsetLeft - currentElement.scrollLeft;
  		totalOffsetY += currentElement.offsetTop - currentElement.scrollTop;
  
  	}
  	while(currentElement = currentElement.offsetParent)
  
  	canvasX = event.pageX - totalOffsetX;
  	canvasY = event.pageY - totalOffsetY;
  
  	return {x:canvasX, y:canvasY};
  
  }
  HTMLCanvasElement.prototype.relMouseCoords = relMouseCoords;
  
  function setNewObjectMass(n) {
  
  	newObjectMass = n;
  
  }
  