$(document).ready(function(){
    $("#topnav li").hover(function() { $(this).children("span").show(); }, function() { $("#topnav li span").hide(); });
    $(".mainpage li").hover(function() { 
        $(this).children("div").show();
        $(this).children("img").animate ({
            height: "315px",
            width: "210px",
            marginLeft: "-3px",
            marginTop: "-3px"
        }, 250
        ).next("span").fadeIn("fast"); }, function() { $(this).children("img").animate({
                height: "300px",
                width: "200px",
                marginLeft: "0",
                marginTop: "0"
        }).next("span").fadeOut("fast").next("div").hide();
        });
    $("#image1").click(function(){ window.location = "hvac.html"; });
    $("#image2").click(function(){ window.location = "cad.html"; });
    $("#image3").click(function(){ window.location = "threedimensional.html"; });
});