jQuery is JavaScript. It is a JavaScript library, so it operates on top of JavaScript. It cannot exist on its own, so you can't use one over the other. You can use just JavaScript or JavaScript and jQuery.
jQuery is designed to make many JavaScript development tasks much easier.
Use jQuery when it will significantly reduce your development time, and you can afford the extra overhead of downloading the library.
A lot of people automatically include jQuery without considering the fact that it might not make the particular development task at hand much easier. This is a bad habit to get into...
Personally my most common uses are:
JavaScript is a scripting language for the web. Microsoft refers to their implementation of it as "JScript" but in terms of syntax it's pretty much the same.
jQuery is a software library, written in JavaScript, whose intention is to help JavaScript developers when writing code that is to be run in a web page.
JavaScript (including jQuery) can be used to add interactivity to a web page beyond that which is possible merely with HTML and CSS. This allows for a more "application-like" experience for the user. Many see it as a bad idea to make a web page which depends on JavaScript, and won't run without it, and insist that JavaScript should only enhance the user experience. However, websites which won't work without JavaScript do exist and are becoming more common.
jQuery runs in JavaScript, and is written in JavaScript. If you are writing JavaScript for a web page, it is often a good idea to also use a library (or framework) like jQuery to make the task of browser-compatibility that much easier. It is like a pre-packaged set of JavaScript routines that you may have otherwise needed to write yourself, packaged in an easy-to-use way.
A drawback of using jQuery is that it is a relatively large file size, which does matter on the web. Some would argue that if you are not using enough of jQuery to justify its file size on your site, you should consider something else (such as a more modular framework, or not using a library/framework at all).
here are some of the major Benifits of jQuery :
Some would argue that it is large, which could affect your web performance... and they would be right. However, because of its popularity, it is likely to have already been used on some site you've visited before. Most browsers these days are good about caching scripts/images, so that download hit is reduced over time.
On the other hand, many new programmers that rely on the framework become very dependent on it, so much so that they lose their ability to evaluate the best tool for the job, and use the most familiar tool that they're used to. These same programmers lose their ability to properly debug and become reliant on an API that has no standard.
What I like using it for is it's cross browser support, which is great for event handling; and whenever you apply dynamic styling to elements on the page (or really anything that requires you needing a more advanced set of elements). Element selection is it's #1 tool, where you can select elements by id, type, attribute, classname, tagname, hierarchical relationship,... all sorts of ways.
jQuery is designed to make many JavaScript development tasks much easier.
Use jQuery when it will significantly reduce your development time, and you can afford the extra overhead of downloading the library.
A lot of people automatically include jQuery without considering the fact that it might not make the particular development task at hand much easier. This is a bad habit to get into...
Personally my most common uses are:
- Complex element selection
- Animation
- Event handling
the difference between JQuery vs JScript.
JavaScript is a scripting language for the web. Microsoft refers to their implementation of it as "JScript" but in terms of syntax it's pretty much the same.
jQuery is a software library, written in JavaScript, whose intention is to help JavaScript developers when writing code that is to be run in a web page.
How we decide what to use and when to use those two technology.
JavaScript (including jQuery) can be used to add interactivity to a web page beyond that which is possible merely with HTML and CSS. This allows for a more "application-like" experience for the user. Many see it as a bad idea to make a web page which depends on JavaScript, and won't run without it, and insist that JavaScript should only enhance the user experience. However, websites which won't work without JavaScript do exist and are becoming more common.
jQuery runs in JavaScript, and is written in JavaScript. If you are writing JavaScript for a web page, it is often a good idea to also use a library (or framework) like jQuery to make the task of browser-compatibility that much easier. It is like a pre-packaged set of JavaScript routines that you may have otherwise needed to write yourself, packaged in an easy-to-use way.
A drawback of using jQuery is that it is a relatively large file size, which does matter on the web. Some would argue that if you are not using enough of jQuery to justify its file size on your site, you should consider something else (such as a more modular framework, or not using a library/framework at all).
here are some of the major Benifits of jQuery :
- crossbrowser support
- easy element selection
- customizable plugins
- large support community
- very popular
Some would argue that it is large, which could affect your web performance... and they would be right. However, because of its popularity, it is likely to have already been used on some site you've visited before. Most browsers these days are good about caching scripts/images, so that download hit is reduced over time.
On the other hand, many new programmers that rely on the framework become very dependent on it, so much so that they lose their ability to evaluate the best tool for the job, and use the most familiar tool that they're used to. These same programmers lose their ability to properly debug and become reliant on an API that has no standard.
What I like using it for is it's cross browser support, which is great for event handling; and whenever you apply dynamic styling to elements on the page (or really anything that requires you needing a more advanced set of elements). Element selection is it's #1 tool, where you can select elements by id, type, attribute, classname, tagname, hierarchical relationship,... all sorts of ways.
Benefits of Javascript -
it's impossible to use jQuery only, all jQuery does is add a $ object to your global scope, with a bunch of methods in it. Even more manipulative libraries like prototype aren't an alternative to javascript, they're a toolbelt to solve common problems.
The main advantages to adding jQuery to your toolbelt would be:
browser compatibility - doing something like .attr() is much easier than the native alternatives, and won't break across browsers.
simplification of usually complicated operations - if you'd like to see a well written cross browser compatible version of an XHR method, take a look at the source for $.ajax - for this method alone it's almost worth the overhead of jQ.
DOM selection - simple things like binding events & selecting DOM elements can be complicated and differ per-browser. Without a lot of knowledge, they can also be easily written poorly and slow down your page.
Access to future features - things like .indexOf and .bind are native javascript, but not yet supported by many browsers. However, using the jQuery versions of these methods will allow you to support them cross browser.
Javascript is no longer just a client side language, and because jQuery is so DOM dependent, it is a terrible candidate to move to the server. I highly recommend putting some time into understanding why you are using jQuery (asking this question is a great first step!), and evaluating when it is necessary.
The main advantages to adding jQuery to your toolbelt would be:
browser compatibility - doing something like .attr() is much easier than the native alternatives, and won't break across browsers.
simplification of usually complicated operations - if you'd like to see a well written cross browser compatible version of an XHR method, take a look at the source for $.ajax - for this method alone it's almost worth the overhead of jQ.
DOM selection - simple things like binding events & selecting DOM elements can be complicated and differ per-browser. Without a lot of knowledge, they can also be easily written poorly and slow down your page.
Access to future features - things like .indexOf and .bind are native javascript, but not yet supported by many browsers. However, using the jQuery versions of these methods will allow you to support them cross browser.
Javascript is no longer just a client side language, and because jQuery is so DOM dependent, it is a terrible candidate to move to the server. I highly recommend putting some time into understanding why you are using jQuery (asking this question is a great first step!), and evaluating when it is necessary.
jQuery can be dangerous, a few of the main dangers are:
code quality - jQuery has a huge community and a low learning curve. This is a perfect storm for lots of poorly written open source plugins.
inefficiency - jQuery is easy to write inefficiently. For instance, using jQuery's each instead of for loops is unnecessary and could have a performance impact in some cases. Lots of good info about this stuff at JSPerf
bloat - jQuery is a huge library. Much of the time, you'll use a small subset of it's features, and grab the whole library. There are some great alternatives that will give you subsets of the features, like zepto.js, and underscore.js - depending on your situation, you can save some bytes by choosing the right library for your needs.
Ultimately, jQuery is an incredibly useful and helpful library, when used properly. However, it is not an alternative to javascript. It is a library, just like zepto.js, YUI, Dojo, MooTools, and Prototype - one of which may be a much better choice for your current project.
Javascript is a misunderstood language, and is only recently being regarded as something more than a scripting language by most people.
code quality - jQuery has a huge community and a low learning curve. This is a perfect storm for lots of poorly written open source plugins.
inefficiency - jQuery is easy to write inefficiently. For instance, using jQuery's each instead of for loops is unnecessary and could have a performance impact in some cases. Lots of good info about this stuff at JSPerf
bloat - jQuery is a huge library. Much of the time, you'll use a small subset of it's features, and grab the whole library. There are some great alternatives that will give you subsets of the features, like zepto.js, and underscore.js - depending on your situation, you can save some bytes by choosing the right library for your needs.
Ultimately, jQuery is an incredibly useful and helpful library, when used properly. However, it is not an alternative to javascript. It is a library, just like zepto.js, YUI, Dojo, MooTools, and Prototype - one of which may be a much better choice for your current project.
Javascript is a misunderstood language, and is only recently being regarded as something more than a scripting language by most people.
I really recommend reading up on it more, here's a few good places to start:
Ben Alman's blog - lots of good best practices here. I don't agree with all of the, but I learn new things from his blog all the time.
Code Academy - basic javascript training. No jQuery here. Sometimes going back to basics helps.
Javascript Garden - a post regarding the more tricky or misunderstood features of javascript. Please read this from time to time, until everything makes sense.
Bocoup - these are training classes. If you're near one, go to it. Many of the best JS speakers and teachers teach these.
Paul Irish's blog - not strictly JS, but plenty of best practices are written about here. Him and Ben's twitter feeds are both great to follow.
Ben Alman's blog - lots of good best practices here. I don't agree with all of the, but I learn new things from his blog all the time.
Code Academy - basic javascript training. No jQuery here. Sometimes going back to basics helps.
Javascript Garden - a post regarding the more tricky or misunderstood features of javascript. Please read this from time to time, until everything makes sense.
Bocoup - these are training classes. If you're near one, go to it. Many of the best JS speakers and teachers teach these.
Paul Irish's blog - not strictly JS, but plenty of best practices are written about here. Him and Ben's twitter feeds are both great to follow.