var overlay_start = 0;
var wrapper_width;
var wrapper_height;

function enlarge(w, h, url) {
    $('body').append(overlay_start = "<div class='overlay_holder' onclick='disable()'></div>");
    $('body').append("<div class='overlay_wrapper'><div class='closebtt' onclick='disable()'></div><div id='overlay_content'><iframe id='myframe' src='' width='" + w + "' height='" + h + "' frameborder='0' scrolling='no'></frame></div></div>");
    wrapper_width = w;
    wrapper_height = h;

    $('.overlay_wrapper').css({
        position: 'fixed',
        padding: '10px',
        left: '50%',
        'margin-left': 0 - (wrapper_width / 2) - 10,
        top: '50%',
        'margin-top': 0 - (wrapper_height / 2) - 10
    });

    $('#overlay_content').css({
        width: wrapper_width,
        height: wrapper_height,
        position: 'relative'
    });

    insert_frame(url);
}

function insert_frame(myurl) {
    $('#myframe').attr('src', myurl);
}

function disable() {
    if (overlay_start) {
        $('.overlay_holder').remove();
        $('.overlay_wrapper').remove();
    }
}