function setFocus() {
document.getElementById("Amount").focus();
}

function calculate(form) {

    //variables
    var selectedWidth  = document.getElementById("Amount").value;
    var selectedHeight = document.getElementById("Height").value;
    var selectedStyle  = document.getElementById("Style").value;
	
    var _350  = 29.50;
    var _550  = 31.60;
    var _750  = 32.80;
    var _950  = 36.70;
    var _1150 = 40.00;
    
    var price = 0;
	
	var style = false;
	
	if(selectedHeight == "200") {
          	price += _350;
    }
    if(selectedHeight == "350") {
            price += _350;
    }
    if(selectedHeight == "550") {
            price += _550; 
    }
    if(selectedHeight == "750") {
            price += _750; 
    }
    if(selectedHeight == "950") {
            price += _950; 
    }
    if(selectedHeight == "1150") {
            price += _1150; 
    }
	// checks if a style has been selected
	if(selectedStyle != "Plain") {
			style = true;		
	}
	// style multiplies by the style price
	if(style) {	
		price = price + 6.30;
	}
	// price multiplies by the width
	var finalPrice = price * selectedWidth;
	// format price to 2 decimal places
	finalPrice = finalPrice.toFixed(2);
    form.total.value = finalPrice;
}