I need help with JavaScript

Hi guys ,please help me to find the output of this JavaScript code,
<html>
<body>
<script type="text/javascript">
var x=0;
while(x != “”){
r = prompt("Enter a number?");
document.write('square(' + x + ') = ' + x*x + '<br>');
}
</script>
</body>
</html>
