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I been learning web development for 1.5 month now, and I am trying to improve my code. I can achieve what I want, but I think my code is really bad.

For example, I have a bunch of jQuery animations and a bunch of function to 'stop' those animations when another animation is starting. The code seems very inelegant, so how should I improve it? I been learning how to write a jQuery plugin, but I don't think it will help in this case.

$(document).ready(function(){

    $("#diagonalLine").show(500);
    $("#line").show(1300);
    $("#start").show(1500);

    $("#centerButton").click(function(){
        $("#diagonalLine").hide(1500);
        $("#line").hide(1300);
        $("#start").hide(500);
        fadeInWaterloo();
        fadeInToronto();
        fadeInTop();
        $("#selectLine").animate({width:'toggle'},1250);;
        $("#diagonalSelectLine").show(1450);
        $("#select").show(1600);    

    });

    $("#waterloo7").mouseenter(function(){
        fadeInTorontoStop();
        fadeInTopStop();
        fadeOutToronto();
        fadeOutTop();

    });
    $("#toronto5").mouseenter(function(){
        fadeInWaterlooStop();
        fadeInTopStop();
        fadeOutWaterloo();
        fadeOutTop();
        //$("#flip").show(1000);
        //$("#infoBox1").slideDown(2000);
    });
    $("#campus").mouseenter(function(){
        fadeInWaterlooStop();
        fadeInTorontoStop();
        fadeOutWaterloo();
        fadeOutToronto();
    });

    $("#waterloo7").mouseleave(function(){
        fadeOutTorontoStop();
        fadeOutTopStop();
        fadeInToronto();
        fadeInTop();

    });     

    $("#toronto5").mouseleave(function(){
        fadeInWaterloo();
        fadeInTop();
    });
    $("#campus").mouseleave(function(){
        fadeInToronto();
        fadeInWaterloo();
    });


    $("#log-in-button").click(function(){sendLogin(); return false;});
    $("#forgotLogin").click(function(){location.href='signUp.html';});
    $("#signUp").click(function(){location.href='signUp.html';});

});


//-------------------------------------Toronto Animation Functions--------------------------
function fadeInToronto(){
    for (var i=1;i<=5; i++){
        $("#toronto"+i).fadeIn(300+i*200);
    }
}
function fadeOutToronto(){
    for (var i=1; i<=5; i++){
        $("#toronto"+i).fadeOut(1100-i*200);
    }
}

function fadeInTorontoStop(){
    for (var i=1;i<=5; i++){
        $("#toronto"+i).fadeIn().stop();
    }
}
function fadeOutTorontoStop(){
    for (var i=1; i<=5; i++){
        $("#toronto"+i).fadeOut().stop();
    }
}
//-----------------------------------End of Toronto Animation---------------------------


//-----------------------------------Waterloo Animation Functions----------------------------
function fadeInWaterloo(){
    $("#waterloo1").fadeIn(0);
    $("#waterloo2").fadeIn(300);
    $("#waterloo3").fadeIn(1300);
    $("#waterloo4").fadeIn(1600);
    $("#waterloo5").fadeIn(1800);
    $("#waterloo6").fadeIn(2000);
    $("#waterloo7").fadeIn(2000);
}

function fadeInWaterlooStop(){
    for (var i=1;i<=7; i++){
        $("#waterloo"+i).fadeIn().stop();
    }
}

function fadeOutWaterloo(){
    var num = 1100;
    for (var i=1; i<=7; i++){
        $("#waterloo"+i).fadeOut(num);
        num = num-200;
    }
}

function fadeOutWaterlooStop(){
    for (var i=1;i<=7; i++){
        $("#waterloo"+i).fadeOut().stop();
    }
}
//----------------------------------------End of Waterloo Animation-------------------


//-------------------------------------Campus Animation Functions--------------------
function fadeInTop(){
    for (var i=1;i<=4; i++){
        var id = "#top"+i;
        $(id).fadeIn(300+i*200);
    }
    $("#campus").fadeIn(1100);
}

function fadeOutTop(){
    $("#top1").fadeOut(1100);
    $("#top2").fadeOut(1100);
    $("#top3").fadeOut(900);
    $("#top4").fadeOut(700);
    $("#campus").fadeOut(500);
}

function fadeInTopStop(){
    for (var i=1;i<=4; i++){
        var id = "#top"+i;
        $(id).fadeIn().stop();
    }
    $("#campus").fadeIn().stop();
}

function fadeOutTopStop(){
    $("#top1").fadeOut().stop();
    $("#top2").fadeOut().stop();
    $("#top3").fadeOut().stop();
    $("#top4").fadeOut().stop();
    $("#campus").fadeOut().stop();
}
//-------------------------------------End of Campus Animation---------------
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  • \$\begingroup\$ The first step to improve your code is to get rid of id's and use common classes. \$\endgroup\$
    – elclanrs
    Commented Sep 21, 2013 at 1:15

2 Answers 2

2
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The general rule is if you're doing something with a static element inside a event, you should cache that reference to this element.

$("#button").click(function(){
    $("#diagonalLine").hide(1500);
}

or

document.getElementById('button').onclick = function(){
    document.getElementById('diagonalLine').style.display='none';
}

Everytime the user click on #button it traverses the DOM to getElementById and find #diagonalLine. With jQuery there's much more overhead involved, it create a new jQuery object, parses the string #diagonalLine, find the element, bind it to the new object and returns it. There are all sort of thing jQuery do under hood to make it "magic".

var diagonalLine = $("#diagonalLine");
$("#centerButton").click(function(){
    diagonalLine.hide(1500);
}

var diagonalLine = document.getElementById('diagonalLine');
document.getElementById('centerButton').onclick = function(){
    diagonalLine.style.display='none';
}

You can also use closures for caching references to elements

$('#button').click=(function(){
    var diagonalLine = $("#diagonalLine");
    return function(){
        diagonalLine.hide(1500);
    }
})();


document.querySelector('#button').onclick=(function(){
    var diagonalLine = document.querySelector('#diagonalLine');
    return function(){
        diagonalLine.style.display='none';
    }
})();
\$\endgroup\$
3
  • \$\begingroup\$ To be pedantic, getElementById is usually implemented using a hash table rather than traversing the DOM, which makes it fairly quick. That said, constructing the jQuery object may make it much more expensive as you point out. \$\endgroup\$
    – icktoofay
    Commented Sep 21, 2013 at 2:29
  • \$\begingroup\$ It may be good practice to name variables with dollar prefix to get a hint it's jQuery object: var $diagonalLine = $("#diagonalLine"); \$\endgroup\$
    – Roman Susi
    Commented Sep 21, 2013 at 6:49
  • \$\begingroup\$ I think it comes to personal preference, IMO it adds pollution to the code. \$\endgroup\$
    – Vitim.us
    Commented Sep 21, 2013 at 8:42
2
\$\begingroup\$

You could certainly use classes in many places to decrease code duplication. For instance, you could add a top class to all of your "top" elements. In that way, you could stop and fadeOut all in one line:

$(".top").fadeOut().stop();

Similarly, this:

for (var i=1;i<=4; i++){
    var id = "#top"+i;
    $(id).fadeIn().stop();
}

would be just this:

$(".top").fadeIn().stop();
\$\endgroup\$

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