Ball Bounce - javascript
<pre><code>function randomXToY(minVal,maxVal,floatVal)
  {
   var randVal = minVal+(Math.random()*(maxVal-minVal));
   return typeof floatVal=='undefined'?Math.round(randVal):randVal.toFixed(floatVal);
  }

  Ball = (function() {

   // constructor
 function Ball(x,y,radius,color){
  this.center = {x:x, y:y};  
  this.radius = radius;               
  this.color = color;
  this.dx = 2;               
  this.dy = 2;        
  this.boundaryHeight = $('#ground').height();
  this.boundaryWidth = $('#ground').width();

  this.dom  = $('&lt;p class="circle"&gt;&lt;/p&gt;').appendTo('#ground');

  // the rectange div a circle
  this.dom.width(radius*2);
  this.dom.height(radius*2);
  this.dom.css({'border-radius':radius,background:color});

  this.placeAtCenter(x,y);         
}

// Place the ball at center x, y
Ball.prototype.placeAtCenter = function(x,y){
  this.dom.css({top: Math.round(y- this.radius), left: Math.round(x - this.radius)});
  this.center.x = Math.round(x);        
  this.center.y = Math.round(y);             
};

Ball.prototype.setColor = function(color) {
  if(color) {
    this.dom.css('background',color);
  } else {
   this.dom.css('background',this.color);
 }           
};

// move and bounce the ball
 Ball.prototype.move = function(){
  var diameter = this.radius * 2;                                               
  var radius = this.radius;  
  if (this.center.x - radius &lt; 0 || this.center.x + radius &gt; this.boundaryWidth ) {
   this.dx = -this.dx;
 }
  if (this.center.y - radius &lt; 0 || this.center.y  + radius &gt; this.boundaryHeight ) {
    this.dy = -this.dy;
  }
  this.placeAtCenter(this.center.x + this.dx ,this.center.y +this.dy);

};

return Ball;
})();

var number_of_balls = 5;
var  balls = [];   

$('document').ready(function(){
  for (i = 0; i &lt; number_of_balls; i++) { 
  var boundaryHeight = $('#ground').height();
  var boundaryWidth = $('#ground').width();
  var y = randomXToY(30,boundaryHeight - 50);
  var x = randomXToY(30,boundaryWidth - 50);
  var radius = randomXToY(15,30);
   balls.push(new Ball(x,y,radius,     '#'+Math.floor(Math.random()*16777215).toString(16))); 
 }
 loop(); 
 });

loop = function(){
 for (var i = 0; i &lt; balls.length; i++){
  balls[i].move();
}

   setTimeout(loop, 8);    
};
</code></pre>

<p>i have not ever used in oops concepts in javascript.Please help anyone how do i change the ball color when ball touch each other</p>

<p>this is the link : <a href="http://jsbin.com/imofat/1/edit" rel="nofollow">http://jsbin.com/imofat/1/edit</a></p>

<p>Thanks is advance:)</p>
