function roll_over(img_name, img_src)
{
    var img = document.getElementById(img_name);
    img.src = img_src;
}

function preloadImages()
{
     // counter
     var i = 0;
     // create object
     imageObj = new Image();
     // set image list
     images = new Array();
     images[0]="_img/home/nav_1_on.gif"
     images[1]="_img/home/nav_2_on.gif"
     images[2]="_img/home/nav_3_on.gif"
     images[3]="_img/home/nav_4_on.gif"
     images[4]="_img/home/nav_5_on.gif"
     images[5]="_img/home/nav_6_on.gif"
     images[6]="_img/home/nav_7_on.gif"
     images[7]="_img/home/nav_8_on.gif"
     // start preloading
     for(i = 0; i <= images.length; i++) 
     {
          imageObj.src=images[i];
          document.write("<img src='" + imageObj.src + "' style='display: none;'/>");
     }
}

//use with onkeypress event
function isnumeric(e)
{
    var keyNum;
    if(e.keyCode)
    {
        keyNum = e.keyCode;
    }
    else
    {
        keyNum = e.which
    }
    var keyChar = String.fromCharCode(keyNum);
    var regex = /\d|\t/
    return regex.test(keyChar)
}

function isReturn(e)
{
    var keyNum;
    if(e.keyCode)
    {
        keyNum = e.keyCode;
    }
    else
    {
        keyNum = e.which
    }
    var keyChar = String.fromCharCode(keyNum);
    var regex = /\r/
    return regex.test(keyChar)
}

function toggleElementsEnabled(checkBox, elementsArr)
{
    var checkBoxElement = document.getElementById(checkBox);
    if(checkBoxElement)
        for(var i = 0; i < elementsArr.length; i++)
        {
            var inputElement = document.getElementById(elementsArr[i]);
            if(inputElement)
                inputElement.disabled = checkBoxElement.checked;
        }
}

function toggleElementsEnabledByBoolean(bool, elementsArr)
{
    for(var i = 0; i < elementsArr.length; i++)
    {
        var inputElement = document.getElementById(elementsArr[i]);
        if(inputElement)
            inputElement.disabled = bool;
    }
}