$('#calculate').click(function(event){
    	
    	event.preventDefault();
    		
    	var submitForm = true;
		var width = $('#mod_pc_width').val();
		var height = $('#mod_pc_height').val();
		var gsm = $('#mod_pc_gsm').val();
		var price = $('#mod_pc_price').val();
		var errormsg = '<p>Sorry, an error occured with this calculation.</p>'
		var type   = $('#mod_price_thousand').attr('checked') == true ? 'thousand' : 'tonne';
		var divid = 'loadcalculation';
	
		if (width == "" || height == "" || isNaN(width) || isNaN(height)) {
			submitForm = false;
			_errorLabel('lblSize');
		} else {
			_normalLabel('lblSize');
		}
		if (gsm == "" || isNaN(gsm)) {
			submitForm = false;
			_errorLabel('lblGsm');
		} else {
			_normalLabel('lblGsm');
		}
		if (price == "" || isNaN(price)) {
			submitForm = false;
			_errorLabel('lblPrice');
		} else {
			_normalLabel('lblPrice');
		}
			
		if (submitForm) {
				_makeRequest('/ajax/module_calculator.php?mod_pc_width='+width+'&mod_pc_height='+height+'&mod_pc_gsm='+gsm+'&mod_pc_type='+type+'&mod_pc_price='+price, divid, errormsg);
		}
    		
    	});