function ExtensionsOkay() {
var extension = new Array();
// Step 1 of 2:
// Replace MyForm with the name of your form and 
//    replace FieldName with the upload field name.

var fieldvalue = document.uploadforma.datoteka.value;


// Step 2 of 2:
// Add the file name extensions that are okay (with 
//    the period), for the variables with their numbers 
//    in sequential order, as many or as few as needed, 
//    starting with 0. (These are case sensitive.)

extension[0] = ".rar";
extension[1] = ".zip";


// No other customization needed.
var thisext = fieldvalue.substr(fieldvalue.lastIndexOf('.'));
for(var i = 0; i < extension.length; i++) {
	if(thisext == extension[i]) { return true; }
	}
alert("Molimo odaberite RAR ili ZIP datoteku.");
return false;
}


function newWindow(url)
{
	window.open(url,'popUpWindow','height=610,width=760,left=100,top=50,resizable=yes,scrollbars=yes,toolbar=no,menubar=no,location=no,directories=no,status=yes');
}