function hideDiv() {
    if ($(window).width() < 1250) {
        $("#tmSkyscraper").hide();
    } else {
        $("#tmSkyscraper").show();
    }
}

//run on document load and on window resize
$(document).ready(function () {
    //on load
    hideDiv();
    //on resize
    $(window).resize(function () {
        hideDiv();
    });

});