I've just learned javascript and jquery a few weeks ago, since then I always use it to position all my divs and stuff in the screen by knowing the size of the screen and the window which I find extremely useful, but now I don't know if is this a good practice, cause it makes my web-pages fully dependant on jquery which I don't know if it may cause some troubles with different browsers.
I would really like to find answers like "Sure is a good practice, use all the scripts you want" cause I'm really loving this javascript stuff but well just tell what you think.
Use JavaScript for behaviors and CSS for styling.
Styling with JavaScript is slower and difficult for another developer/designer to figure out what you did.
Also if you use Firebug or Chrome Web Inspector you can not see where your styling is coming from.
Optionally set classes from JavaScript and not specific styling. You can transition between classes to create a nice effect. But at least your colleague can see where the styles are defined and change it.
I'm sorry, but I'm going to burst your bubble, somewhat.
It's somewhat OK to do it - as long as the page looks OK if you disable Javascript, as well. I would say it should look even better than OK. I would also say that you should only do that if the functionality of your site really demands Javascript, as well.
Keep in mind that a certain percentage of users will have Javascript disabled. I've seen sites that look horrible this way (I use NoScript on Firefox, and selectively enable Javascript as I browser), and a couple where nothing at all appears without JS enabled.
Bad.
As Darin notes, you can (and should!) use CSS for positioning and styling. That is what it was made for! Feel free to enhance the page with Javascript, but keep in mind what I say above!
You could use CSS for positioning and styling of elements. That's what it was designed for.
It's okay to use it for positioning in some cases, but using CSS is the better practice whenever applicable.
Well, In my opinion you should avoid it as often as possible. But I know sometime you don't have the choice.
And yea you can make great web apps using scripts.
It depends what you're positioning.
CSS should be your first choice for positioning standard, run-of-the-mill sections and elements of a webpage. To opt for JavaScript in these cases suggests a lack of understanding of CSS.
Likewise if you find yourself using JS to position things for different devices. Again, CSS has evolved; media queries came along for that. Rule: always exhaust CSS possibilities first.
That said, it would be oversimplification to suggest that JavaScript never be used for positioning. All of us, rightly or wrongly, have resorted (and it is just that, resorting) to JS in order to get things to look right cross-browser, particularly where support for older IEs is concerned.
But by far the biggest use case for JS positioning is for modern web aps and games. If you're building a game with random asteroids dotted around, JS is absolutely the choice for that, since the positions are based on calculation and computation.
Finally, bear in mind that when you position in JS, you are of course still using CSS. JS doesn't have its own, concurrent styling/positioning system - it simply sets CSS properties. It is simply able to do so more dynamically and conditionally than flat CSS.
It is almost certainly bad practise. Use CSS for styling - JavaScript to do this is slower, more work, and more prone to breaking.
If you're positioning everything absolutely (fixed coordinates) it won't look good on screens of different resolutions. There's no real answer to this question.. scripts have their place, and you can use all the scripts you want... Positioning all of the elements of your layout, however, is not a job for JS. Use CSS for that.
I'd start here: Starting with HTML + CSS
There is not one method for all situations. Each web application needs to employ the right tools and practices to achieve its goals. This varies so much between applications that there is not a "correct" answer to your question.
Related
Are there some problems that prevent people from creating it? Is it too complicated?
Maybe there is just no need for that?
Was it created it already and I just can't find it?
I imagine it to be a js based library and work this way:
It checks if the browser supports flexbox natively;
If it doesn't, it parses CSS and checks if an element has flexbox related rules;
If it does, it tries to emulate these rules via javascript by calculating all positions and sizes of the children elements and position them using position: absolute;.
Basically, the same thing that Masonry and similar libraries do, but with flexbox rules. Would that be possible to do?
Edit: this question doesn't explain why it can't be done.
There is actually a library that does exactly what I wanted: https://github.com/jonathantneal/flexibility
It's in the very early phase of development, but hopefully it will be viable soon.
"emulate these rules via javascript" is the "most impossible" part.
flex box is purely position:static thing, you cannot move it on
position:absolute layer (there are too many things behind this);
flex box calculations are made on so called rendering tree that is not available to JS;
In order JS to be used for static layout purposes browsers should have a mechanism to hook up users code to rendering tree formation and layout:
div { layout: myFlexManager url(my-layouts.js); }
But as soon as browsers will have such a facility the flexbox will be thrown away as this is the worst and ugliest CSS spec ever produced - community will come up with something better - simpler and more practical.
I'm using the following script for entrance animations in a project: www.justinaguilar.com/animations/
My concern is that this entrance animations rely on "visibility: hidden" property in CSS in order to work. I'm afraid that if JavaScript or CSS aren't available or don't work properly on the user end, the content wont be displayed at all.
Should I be concerned about this?
Is there a better alternative or some fallback plan I could implement?
Thanks.
I think about that in this way.
If this is your only problem about JS disabled, or if you have just a little JS in your page, maybe it is worth find a way to fix it (probably turn the animations off and making the site a little "uglier"). In that way, you're providing access for everyone (and that was a good concept).
But, personally, I've never cared about that. All websites that I've developed contains a lot of JS (with Ajax calls, for instance), it'd imply in a lot of (unnecessary, in my opinion) work for making them functional without JS.
Searching about it, I've read this question. In 2010, 0.25% of the users in Brazil (country where I live) had JS disabled in their browsers. This number should be even less these days. And honestly, I have better things to do with my time instead of caring about these people.
In short terms, my opinion is: if you just use JS a little (or if it's really necessary make this site work without JS), fix it. In all other cases, forget about that and focus on what really matters.
EDIT:
If you wanna guarantee the content will be displayed, you can hide the element via JS. In this way, the element will only be hidden when CSS and JS are on.
<div class="element-to-hide" style="visibility:visible;"></div>
<style type="text/css">
.hide {
visibility: hidden;
}
</style>
<script>
$('.element-to-hide').addClass('hide');
</script>
I am a beginner in web-designing. I use css, javascript, jquery for web development.
There are times when an effect can be achieved with all of the three. Like a simple mousehover effect can be achieved with css :hover, javascript's onmousehover(), and jquery's $(#id).hover()
jquery fade-in, fade-out effect can also be simulated using css transition.
My question is: If an effect can be achieved using all three. Do i need to give preference to stylesheet language or javascript or jquery. using which among above will increase performance and will load the webpage faster.
First of all give a preference to that way which you can do faster (computers cost a little, programmer cost a lot). Also pay attention of how you do it - if you have to write tons of css code instead of couple lines in jQuery - use jQuery for sure.
css speed > javascript speed > jquery speed. As i seen some benchmarks native js is like 10-100 times faster than jQuery (depending on browser/selectors etc...).
Depending on situation - if you really need to optimize your interface -> find a bottlneck first, dont't optimize too early, it's evil
jquery has the advantage of working across multiple browsers but suffers some slowdowns to do this. A custom javascript solution may or may not work on all browsers, but it might be faster than jQuery if you're really good at writing fast javascript. Using css to achieve an effect has the advantage of working on all browsers that comply to the css standard and browsers should be highly optimized to render css very fast.
I think it's more an issue of what browsers you want to support, personal preference and coding styles than it is an issue of speed, but here is some information and benchmarks:
Which is faster? - modifying css property or adding class in jquery
http://jsperf.com/jquery-css-vs-native-dom/16
http://jsperf.com/jquery-css-vs-css/4
http://jsperf.com/jquery-css-vs-getcomputedstyle/2
Edit: Agree with Sergio, early optimization is the root of all evil. Write the code first, look for bottlenecks and treat them last.
Depends on what you want to achieve or the scenario.
I personally like css,but sometimes to achieve cross browser compatibility or some fancy effects i use jquery.
Jquery can be customized a lot,lots of options are also available,but it affects the page loading time. I prefer jquery or javascript.
With CSS3,lots of effects that could only be done with jquery are achievable now,but it only supports modern browsers.
I have written a Javascript/jQuery script. Its purpose is to serve as a responsive background image slider.
It is viewable here:
http://new.upserver.co.uk/rbis/
My question is this;
While the code functions correctly, it can be slow/laggy. Especially when additional animation related plugins appear on the same page (i.e. nivoslider).
I have seen many similar sliders that handle chunky images perform effortlessly and am concerned and wondering how this code could be optimised to perform better? the javascript in question is located in file http://new.upserver.co.uk/rbis/rbis.js
Many thanks for all suggestions.
Regards
jQuery animate is rarely the right tool for providing animation. Take a look at this rather contrived example I produced recently: http://css3.bradshawenterprises.com/demos/speed.php.
I would recommend using CSS transitions in normal browsers, and only using the old way of doing it using javascript in old browsers.
A good way to do that is to use something like http://playground.benbarnett.net/jquery-animate-enhanced/, though I have had some issues with that, and instead use my own methods of doing it.
I want to apply ALL the CSS styles 100% with JQuery/JavaScript
But is is bad idea to do this?
Why would you create that overhead in javascript when straight HTML/CSS is fully capable of handling it? (in fact intended to)
Also, you're adding an unnecessary requirement to the styling of your site: having javascript enabled.
Main reason IMHO: Performance! Native CSS is much faster than JS.
Also worth mentioning:
Doesn't work for users with NoScript etc.
Overhead. Not such a big deal i think. There are more important things to optimize.
If you lazy load stuff, e.g. by using jQuery.load(), you have to reapply your styles to these elements. Not nice :/
Conclusion: CSS is made for styling, JS isn't.
If your visitor has javascript disabled, they'll see an ugly white page without any styling.
I don't see why you would do this, to be honest. It's not user-friendly.
Use a stylesheet.
A lot of people say to apply classes not individual styles.
You will see varying levels of performance degradation across different browsers. It's faster and cleaner to let the application render the styled HTML page because that's what it's optimized to do.
If you're dynamically loading content and already have fade effects/transitions so your content is only revealed after it's styled, you might be ok.
if you are going to do this, only apply styles with jQuery (rather than using javascript) to maintain cross-browser compatibility.
I would recommend against your approach because of the time it will take jQuery to loop through all of your elements and apply styles.
something like $('span').css(...); has to traverse the entire DOM and loop through a collection of elements. $('#title').css(...); does not have to loop through the entire DOM because it immediately knows where to look.
Also, browsers are designed to process stylesheets and render your styled elements very quickly.