// Preload the images
// ==================
myImg = new Image();
myImg.src = "loading.gif";

$(document).ready(
	function() {
		$("#convert").click
		(
			function() {
				if(check_input())
				{
					$("#result").html('<img src="loading.gif" width="32" height="32" alt="Converting..." /> Converting, please wait...');
					 $.ajax({
						   type: "POST",
						   url: "currency_converter.php",
						   data: "amount=" + $("#amount").val() + "&from=" + $("#from").val() + "&to=" + $("#to").val(),
						   success: function(html){
							 $("#result").html(html);
						   }
						 });
				}
			}
		);
	}
);

function check_input()
{
	var err = false;
	var err_mess = '';
	
	if($("#amount").val()=='')
		{
			err_mess +='Amount field is require!<br />';
			err = true;
		}
	else
	{
		if(isNaN($("#amount").val()))
		{
			err_mess += 'Amount must be number!<br />';
			err = true;
		}
		if($("#amount").val().indexOf('-')!=-1)
		{
			err_mess += 'Amount must be positive number!<br />';
			err = true;
		}
	}

	if(err)
		{
			$("#result").html(err_mess);
			return false;
		}
	else
		return true;	
}