Frog Jump Problem

A small frog wants to get to the other side of the road. The frog is currently located at position X and wants to get to a position greater than or equal to Y. The small frog always jumps a fixed distance, D. Count the minimal number of jumps that the small frog must perform to reach its target.

HTML

<p>
A small frog wants to get to the other side of the road. The frog is currently located at position X and wants to get to a position greater than or equal to Y. The small frog always jumps a fixed distance, D.
Count the minimal number of jumps that the small frog must perform to reach its target.
</p>
<div>
X = <input id="X" type="text">
</div>
<div>
Y = <input id="Y" type="text">
</div>
<div>
D = <input id="D" type="text">
</div>
<div>
 <button id="Calculate">Calculate Min Hops</button>
</div>
<div>
 <div id="Result"></div>
</div>

CSS

div { line-height: 30px;}

JavaScript

function frogMinJumps(x,y,d) {
	 var numberOfJumps;
   // Assume x,y and d are 1 .. 1,000,000,000
   if (x < 1 || y < 1 || d < 1) {
	   return 'Values must be greater than 1';
   }
   if (x > 1000000000 || y > 1000000000 || d > 1000000000) {
	   return 'Values must be less than 1,000,000,000';
   }
   if ( (y-x) < d ) {
     numberOfJumps = 1;
   } else {
     if ( (y-x) % d === 0) {
       numberOfJumps = parseInt((y-x)/d);
     } else {
       numberOfJumps = parseInt(((y-x)/d)+1);
     }
   }
   
   return numberOfJumps.toString();
}

document.querySelector('#Calculate').addEventListener('click', function(){
	var x = parseInt(document.querySelector('#X').value);
  var y = parseInt(document.querySelector('#Y').value);
  var d = parseInt(document.querySelector('#D').value);
	document.querySelector('#Result').textContent = frogMinJumps(x,y,d);
}, false);