function calcTireDiameter()
    {
        var width = document.getElementById('txtTireWidth').value;
        var aspect = document.getElementById('txtTireAspect').value;
        var wheel = document.getElementById('txtTireWheel').value;

        if(width > 1 && aspect > 1 && wheel > 1)
        {
            var diameter = (((width * (aspect / 100) * 2) / 25.4) * 1) + (wheel * 1);
            document.getElementById('txtTireDiameter').value = diameter.toFixed(2) + '"';
            
            colorBorder('green', 'txtTireDiameter');
            showControl('btnTireSave');
        }
    }
    
    function saveTireDiameter()
    {
        var width = document.getElementById('txtTireWidth').value;
        var aspect = document.getElementById('txtTireAspect').value;
        var wheel = document.getElementById('txtTireWheel').value;
        var sizeString = width + '/' + aspect + '-' + wheel;
        
        var diameter = document.getElementById('txtTireDiameter').value;
        
        var oldSave = document.getElementById('lblTireSave').innerHTML;
        document.getElementById('lblTireSave').innerHTML = oldSave + '<br />' + sizeString + ' : ' + diameter;
        hideControl('btnTireSave');

        document.getElementById('txtTireWidth').value = '';
        document.getElementById('txtTireAspect').value = '';
        document.getElementById('txtTireWheel').value = '';
        document.getElementById('txtTireDiameter').value = '';        
        
        colorBorder('orange', 'txtTireDiameter');
    }
    
    function calc(x, map, kpa, psi)
    {
        var tbMap = document.getElementById('tbMap');
        var tbKpa = document.getElementById('tbKpa');
        var tbPsi = document.getElementById('tbPsi');
        
        var answer = null;

        switch(x)
        {
            case 'map':
                answer = (kpa - (psi / (14.7/101.3))).toFixed(2);
                //answer = (psi - (kpa*mult)) / (mult*(-1));
                tbMap.value = answer;
                tbMap.style.border = "solid 1px green";
                tbKpa.style.border = "solid 1px orange";
                tbPsi.style.border = "solid 1px orange";
                break;
            
            case 'kpa':
                answer = (psi * 101.3 / 14.7 + (map * 1)).toFixed(2);
                tbKpa.value = answer;
                tbMap.style.border = "solid 1px orange";
                tbKpa.style.border = "solid 1px green";
                tbPsi.style.border = "solid 1px orange";                
                break;
            
            case 'psi':
                answer = ((kpa - map) * (14.7/101.3)).toFixed(2);
                tbPsi.value = answer;
                //2.036;
                document.getElementById('lblHg').innerHTML = (answer * 2.036 * -1).toFixed(2);
                tbMap.style.border = "solid 1px orange";
                tbKpa.style.border = "solid 1px orange";
                tbPsi.style.border = "solid 1px green";                
                break;
        }          
    }
    function clearKpaColors()
    {
        document.getElementById('tbMap').style.border = 'solid 1px orange';
        document.getElementById('tbKpa').style.border = "solid 1px orange";
        document.getElementById('tbPsi').style.border = "solid 1px orange";
        
        clearHg();
    }
    function clearHg()
    {
        document.getElementById('lblHg').innerHTML = "";
    }
    
    function colorBorder(color, control)
    {
        document.getElementById(control).style.border = 'solid 1px ' + color;
    }
    
    function hideControl(control)
    {
        document.getElementById(control).style.display = 'none';
    }
    
    function showControl(control)
    {
        document.getElementById(control).style.display = '';
    }
    
    function openTool(control)
    {
        document.getElementById(control).style.visibility = 'visible';
        bringTop(control);
    }
    
    function bringTop(control)
    {
        document.getElementById('hfZ').value++;
        document.getElementById(control).style.zIndex = document.getElementById('hfZ').value;
    }