Book Image

jQuery HOTSHOT

By : Dan Wellman
Book Image

jQuery HOTSHOT

By: Dan Wellman

Overview of this book

jQuery is used by millions of people to write JavaScript more easily and more quickly. It has become the standard tool for web developers and designers to add dynamic, interactive elements to their sites, smoothing out browser inconsistencies and reducing costly development time.jQuery Hotshot walks you step by step through 10 projects designed to familiarise you with the jQuery library and related technologies. Each project focuses on a particular subject or section of the API, but also looks at something related, like jQuery's official templates, or an HTML5 feature like localStorage. Build your knowledge of jQuery and related technologies.Learn a large swathe of the API, up to and including jQuery 1.9, by completing the ten individual projects covered in the book. Some of the projects that we'll work through over the course of this book include a drag-and-drop puzzle game, a browser extension, a multi-file drag-and-drop uploader, an infinite scroller, a sortable table, and a heat map. Learn which jQuery methods and techniques to use in which situations with jQuery Hotshots.
Table of Contents (18 chapters)
jQuery HOTSHOT
Credits
Foreword
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Detecting when the page has scrolled


Our next task is to detect when the page has been scrolled and fix the element in place when that occurs. Detecting the scroll event is made easy for us by jQuery, as is setting the position to fixed, because there are simple jQuery methods we can call to do these exact things.

Engage Thrusters

Add the following code to the script file directly after the variables we initialized in the last task:

win.one("scroll", function () { 
    fixedEl.css({
        width: width,
        position: "fixed",
        top: Math.round(initialPos.top),
        left: Math.round(initialPos.left)
    });
});

Objective Complete - Mini Debriefing

We can use jQuery's one() method to attach an event handler to the window object that we stored in a variable. The one() method will automatically unbind the event handler as soon as the event is detected for the first time, which is useful because we only need to set the element to position:fixed once. In this example we are looking for...