// numeric only input
function isNumberKey(evt) {
    var charCode = (evt.which) ? evt.which : event.keyCode
    if (charCode > 31 && (charCode < 48 || charCode > 57))
        return false;

    return true;
}

// toggle a container
function unhide(divID) {
    var item = document.getElementById(divID);
    if (item) {
        item.className = (item.className == 'hidden') ? 'unhidden' : 'hidden';
    }
}

// hide a container
function hide(divID) {
    var item = document.getElementById(divID);
    if (item) { item.className = 'hidden'; }
}

// calculate dimensions
function CalculateDimensions() {

    var percent = 1.05;
    if (document.getElementById('ctl00_ContentPlaceHolder1_radWastage8').checked)
    {
        percent = 1.08;
    }

    var totalarea = 0;
    
    for (i = 1; i < 11; i++) {

        var txtLength = document.getElementById('ctl00_ContentPlaceHolder1_txtLength' + i);
        var txtWidth = document.getElementById('ctl00_ContentPlaceHolder1_txtWidth' + i);
        var lblArea = document.getElementById('ctl00_ContentPlaceHolder1_lblArea' + i);

        var wid = parseFloat(txtWidth.value);
        var len = parseFloat(txtLength.value);

        var area = 0;
        
        if (!(isNaN(wid) || isNaN(len)))
        {
            area = wid * len;
        }

        lblArea.innerHTML = area.toFixed(2);

        totalarea += area;
    }

    totalarea = totalarea * percent;
    var lblTotal = document.getElementById('ctl00_ContentPlaceHolder1_lblTotal');
    lblTotal.innerHTML = totalarea.toFixed(2);
    
}