How to avoid Conflict in jQuery

Many JavaScript libraries use $ as a function or variable name, just as jQuery does. In jQuery's case, $ is just an alias for jQuery, so all functionality is available without using $. If we need to use another JavaScript library alongside jQuery, we can return control of $ back to the other library with a call to $.noConflict():

Creates a different alias instead of jQuery to use in the rest of the script.

var $j = jQuery.noConflict();
// Do something with jQuery
$j("div p").hide();

// Do something with another library's $()
$("content").style.display = 'none';

Tips for using jQuery

Find if something is hidden:

We use .hide(), .show() methods in jquery to change the visibility of an element. Use following code to check the whether an element is visible or not.

if($(element).is(":visible") == "true") {
//The element is Visible
}

Center an element on the Screen:

To make align the element to center.

jQuery.fn.center = function () {
this.css("position","absolute");
this.css("top", ( $(window).height() - this.height() ) / 2+$(window).scrollTop() + "px");
this.css("left", ( $(window).width() - this.width() ) / 2+$(window).scrollLeft() + "px");
return this;
}

//Use the above function as:
$(element).center();

Disable right-click contextual menu:

There’s many Javascript snippets available to disable right-click contextual menu, but JQuery makes things a lot easier:

$(document).ready(function(){
$(document).bind("contextmenu",function(e){
return false;
});
});

Get mouse cursor x and y axis:

This script will display the x and y value – the coordinate of the mouse pointer.

$().mousemove(function(e){
//display the x and y axis values inside the P element
$('p').html("X Axis : " + e.pageX + " | Y Axis " + e.pageY);
});
<p></p>

Font resizing:

Font Resizing is a very common feature in many modern websites. Here’s how to do it with JQuery.

$(document).ready(function(){
// Reset Font Size
var originalFontSize = $('html').css('font-size');
$(".resetFont").click(function(){
$('html').css('font-size', originalFontSize);
});
// Increase Font Size
$(".increaseFont").click(function(){
var currentFontSize = $('html').css('font-size');
var currentFontSizeNum = parseFloat(currentFontSize, 10);
var newFontSize = currentFontSizeNum*1.2;
$('html').css('font-size', newFontSize);
return false;
});
// Decrease Font Size
$(".decreaseFont").click(function(){
var currentFontSize = $('html').css('font-size');
var currentFontSizeNum = parseFloat(currentFontSize, 10);
var newFontSize = currentFontSizeNum*0.8;
$('html').css('font-size', newFontSize);
return false;
});
});

Preloading images:

When you’re using images in Javascript, a good thing is to preload it before you have to use it. This code will do the job:

jQuery.preloadImages = function()
{
for(var i = 0; i").attr("src", arguments[i]);
}
};

// Usage
$.preloadImages("image1.gif", "/path/to/image2.png", "some/image3.jpg");

SlideShow using jQuery

Creating Image Slide Show using jQuery:

In the code below you will see a surrounding div (id slideshow-area) which holds our slideshow content scroll area and our next and previous buttons. Inside our scroll area we have a div to hold the content and finally the content itself. As far as html goes this is pretty simple stuff.

<div id="slideshow-area">
<div id="slideshow-scroller">
<div id="slideshow-holder">
<div class="slideshow-content">
<img src="eureka_small.jpg" />
</div>
<div class="slideshow-content">
<img src="wallace_gromit_small.jpg" />
</div>
<div class="slideshow-content">
<img src="dead_like_me_small.jpg" />
</div>
</div>
</div>
<div id="slideshow-previous"></div>
<div id="slideshow-next"></div>
</div>

CSS is up next, it is slightly more complicated than the html but nothing too crazy. The first piece to look at is the positioning and sizing of main slide show area and scroller, which can have pretty much the same css. We do however add a border to our area to bring it out a little. The code below is fairly understandable, I make sure to set the position to relative so that I can easily position the next and previous buttons absolutely.

#slideshow-area, #slideshow-scroller {
width: 500px;
height: 500px;
position: relative;
overflow: hidden;
margin: 0 auto;
}

#slideshow-area {
border: 1px solid #000;
}

We are also going to set the height of the content holder to 500px, same as the area.

#slideshow-holder {
height: 500px;
}

The next two items are the previous and next buttons. They take a little bit more work to make sure they are in the correct position. The buttons also have background images for pretty arrows (sorry IE6 users it may look bad since the arrows are png files). I also set the cursor to hand and pointer - for browser compatibility. And finally we also have classes to identify and float left each piece of content in the slideshow.

#slideshow-previous, #slideshow-next {
width: 50px;
height: 50px;
position: absolute;
background: transparent url("arrow_left.png") no-repeat 50% 50%;
top: 225px;
display: none;
cursor: pointer;
cursor: hand;
}

#slideshow-next {
display: block;
background: transparent url("arrow_right.png") no-repeat 50% 50%;
top: 225px;
right: 0;
}

.slideshow-content {
float: left;
}

Well onto the real work, we now have to create the JavaScript to handle our functionality. jQuery makes this relatively simple though. First item is adding code to the document ready event.

var totalSlides = 0;
var currentSlide = 1;
var contentSlides = "";

$(document).ready(function(){
$("#slideshow-previous").click(showPreviousSlide);
$("#slideshow-next").click(showNextSlide);

var totalWidth = 0;
contentSlides = $(".slideshow-content");
contentSlides.each(function(i){
totalWidth += this.clientWidth;
totalSlides++;
});
$("#slideshow-holder").width(totalWidth);
$("#slideshow-scroller").attr({scrollLeft: 0});
updateButtons();
});

Next we need to create the two functions showPreviousSlide and showNextSlide. These two functions do mainly three things: change current slide number, update the buttons, and scroll the content. These functions along with support functions are below.

function showPreviousSlide()
{
currentSlide--;
updateContentHolder();
updateButtons();
}

function showNextSlide()
{
currentSlide++;
updateContentHolder();
updateButtons();
}

function updateContentHolder()
{
var scrollAmount = 0;
contentSlides.each(function(i){
if(currentSlide - 1 > i) {
scrollAmount += this.clientWidth;
}
});
$("#slideshow-scroller").animate({scrollLeft: scrollAmount}, 1000);
}

function updateButtons()
{
if(currentSlide < totalSlides) {
$("#slideshow-next").show();
} else {
$("#slideshow-next").hide();
}
if(currentSlide > 1) {
$("#slideshow-previous").show();
} else {
$("#slideshow-previous").hide();
}
}