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

function validateForm(form) {
    
    if(document.getElementById("Amount").value == null) {
        alert("Please enter a width");
    }
    if(document.getElementById("Height").value == null) {
        alert("Please select a height");
    }
    if(document.getElementById("Style").value == null) {
        alert("Please select a style");
    }
}

function calculate(form) {
    //variables
    var selectedWidth  = document.getElementById("Amount").value;
    var selectedHeight = document.getElementById("Height").value;
    var selectedStyle  = document.getElementById("Style").value;

    const _350  = 29.50;
    const _550  = 31.60;
    const _750  = 32.80;
    const _950  = 36.70;
    const _1150 = 40.00;
    
    var price = 0;
	
    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; 
    }
    
var finalPrice = price * selectedWidth; 
if(finalPrice <= 100) {
    finalPrice = 100;
}
finalPrice = Math.round(finalPrice*100)/100;
form.total.value = finalPrice;
}