// these functions may be used in every other script

function getElement(id) {
    return document.getElementById(id);
}

// used for main page resizing (when the page loads)
function resize() {
    var mainContent = getElement('mainContent'),
        sidebar1 = getElement('sidebar1');
    
    if (sidebar1.offsetHeight > mainContent.offsetHeight) {
        mainContent.style.height = sidebar1.offsetHeight + 'px';
    }
}

// check is an input node has any value set
function isEmpty(node) {
    if (node.value === '') {
        return true;
    }
    return false;
}

// check a text input node if it's value is a valid email
function isValidEmail(node) {
    if (-1 === node.value.search(/^\w+((-\w+)|(\.\w+))*\@[A-Za-z0-9]+((\.|-)[A-Za-z0-9]+)*\.[A-Za-z0-9]+$/)) {
        return false;
    }
    return true;
}

// check a text input node, if it's value is a valid url
function isValidUrl(node) {
    var r = new RegExp("^(ftp|http|https)://([a-zA-Z0-9-_]+[.])*[a-zA-Z0-9-_]+[.][a-zA-Z]{2,4}/?$", "i"),
        res = r.test(node.value);

    if (res) {
        return true;
    }
    return false;
}