CodingForums.com - Help Please with Javascript

I need help with this code. I have written it and the only part that works is the calculation of cost for the fruits. The other part where requires to validate the values does not work i.e if i put the values beyond 99 in textboxes, it is suppose to say..the values are suppose to be between 0-99, but it does not do that. Any help would be appreciated.

Thanks

Code:

<?xml version = "1.0" encoding = "utf-8" ?>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org//TR/xhmtl/DTD/xhtml-strict.dtd ">

<html xmlns = "http:www.w3.org/1999/xhtml">

<head>

<title> nochange.html </title>

<script type = "text/javascript" src = "nochange.js" ></script>

<script>

function validateForm(){

  document.getElementById("Apple").onblur=function(){

  if(this.value==""){alert("Please Enter values");return}

  if(parseInt(this.value)<0 || parseInt(this.value)>99 ){alert("values should be betwween 0-99 ");}   

};



  document.getElementById("Orange").onblur=function(){

    if(this.value==""){alert("Please enter values");return}

     if(parseInt(this.value)<0 || parseInt(this.value)>99 ){alert("values should be between 0-99");}     

};



  document.getElementById("Banana").onblur=function(){

  if(this.value==""){alert("Please enter values");return}

   if(parseInt(this.value)<0 || parseInt(this.value)>99 ){alert("values should be between 0-99");}   

};



document.getElementById("btnTotalCost").onclick = function(){

        if( document.getElementById("Apple").value==""

            document.getElementById("Orange").value==""

            document.getElementById("Banana").value==""

        ){

            alert("Enter all the values properly");

        }    

    };               

}



</script>

</head>

<body>

<form action = "">

<h3> Fruits Shop </h3>

<table border = "border">

<tr>

<th> Product Name </th>

<th> Price </th>

<th> Quantity </th>

</tr>

<tr>

<th> Apple </th>

<td> $0.59 </td>

<td> <input type="text" id="Apple" size = "2" /> </td>

</tr>

<tr>

<th> Orange </th>

<td> $0.49 </td>

<td> <input type="text" id="Orange" size = "2" /> </td> 

</tr>

<tr>

<th> Banana </th>

<td> $0.39 </td>

<td> <input type="text" id="Banana" size = "2" /></td>

</tr>

</table>

<p>

<input type="button" id = "btnTotalCost" value = "Total Cost" onclick="computeCost();" />

<input type="text" size="5" id ="cost" onfocus="this.blur();" />

</p>

<p>

<input type = "Submit"  value = "Submit" />

<input type = "reset" value = "Clear" />

</p>



<script>

function computeCost() {

var apple = document.getElementById("Apple").value;

var orange = document.getElementById("Orange").value;

var banana = document.getElementById("Banana").value;

var totalCost = (apple * 0.59 + orange * 0.49 + banana * 0.39)*1.05;

document.getElementById("cost").value =totalCost;

}

</script>

</form>

</body>

</html>