I believe that this question has been asked in a few different forms, but I've read quite a few different responses.
At first, I had a web-application written with mostly jQuery that would make use of servlets to retrieve information from various locations JavaScript could not access (ie. Feeds, images from a server, etc.). Now, however, I've been told to do away with the servlets and application configuration classes so that this project of mine contains only HTML, CSS, and JavaScript/jQuery. Rather than pulling the images off of the server, I need to retrieve them from a local file on the computer. I know that allowing this might seem like terrible design, but it's what I've been asked to do. At any rate, what I really need to do is count the number of image files in a directory and then perhaps compile an array of the filenames themselves. I could do this fine in Java when using the servlets, but without them, I'm not sure how or even if this can be done.
I'm basically trying to use the jQuery Cycle plug-in to cycle through these images like a slideshow. I inject (or $("#div").append()) these images into the div by using a loop based on the number of images present.
So, is there a way I can do this with using JavaScript, HTML, jQuery plug-in, etc? I'd like to avoid using PHP and Java at this point...
You can't just read a directory with JavaScript; however, there appears to be a way to "exploit" how browsers function using http://www.irt.org/articles/js014/. It may not be pretty, but the demo works in the latest Chrome and IE7-9 for me. I'm sure some of the techniques could be updated to use cleaner code if you'd like to improve upon it.
EDIT:
Another technique you could use can be found in Javascript read files in folder
It definitely looks to be a cleaner solution. What I'd recommend is extracting the body contents to inject into a hidden div or using the path for an iframe that you can read from.
Related
I would like to generate a PDF portfolio using JS from an HTML/CSS page on a local machine. I would use a PDF template file which includes a PDF portfolio Navigator in SWF form. I have successfully accomplished this using C# and a command line program, but can not identify the proper Javascipt components to do this browser-side or pseuo-server with Node.js. Basically, I am looking for something which will allow me to append a PDF to a new or existing PDF via configuration choices and an 'assemble' action using a JS or HTML button. iTextSharp provides the required PDF interaction functionality, but I can not figure out to run this inside an HTML to allow configuration via the HTML/CSS DOM (i.e. checkboxes, text field desciptors, etc...). Does a library with this type of functionality exist?
So you want to create a PDF using JavaScript?
On a quick google search, I found what appears to be a javascript library for creating and manipulating PDFs call jsPDF
If you want information on how to upload files with JavaScript alone, here is an article on how to do that. It also shows you how to use the file element.
For style, I recommend using a CSS Framework is you don't know much about CSS. I personally use Twitter Bootstrap for quickly prototyping things. It's quick and easy, and has good documentation. You can also use this to see how to make a form in HTML. I haven't got any good starter tutorials for HTML off the top of my list, sorry.
If you don't know much about JavaScript, when it comes to getting the options from the form, so that you can use them as configuration options, I'd suggest using the jQuery framework. It'll help you get up and running quickly enough
Note, all of this shouldn't replace basic training in JavaScript and HTML/CSS. Frameworks make things simpler, but if you don't know how to do something without a framework, you're going to have a hard time with a lot of the more complicated things. This goes for every language
I just did a proof of concept/demo for a web app idea I had but that idea needs to be embedded on pages to work properly.
I'm now done with the development of the demo but now I have to tweak it so it works within a tag on any websites.
The question here is:
How do I achieve this without breaking up the main website's stylesheets and javascript?
It's a node.js/socket.io/angularjs/bootstrap based app for your information.
I basically have a small HTML file, a few css and js files and that's all. Any idea or suggestions?
If all you have is a script tag, and you want to inject UI/HTML/etc. into the host page, that means that an iframe approach may not be what you want (although you could possibly do a hybrid approach). So, there are a number of things that you'd need to do.
For one, I'd suggest you look into the general concept of a bookmarklet. While it's not exactly what you want, it's very similar. The problems of creating a bookmarklet will be very similar:
You'll need to isolate your JavaScript dependencies. For example, you can't load a version of a library that breaks the host page. jQuery for example, can be loaded without it taking over the $ symbol globally. But, not all libraries support that.
Any styles you use would also need to be carefully managed so as to not cause issues on the host page. You can load styles dynamically, but loading something like Bootstrap is likely going to cause problems on most pages that aren't using the exact same version you need.
You'll want your core Javascript file to load quickly and do as much async work as possible as to not affect the overall page load time (unless your functionality is necessary). You'll want to review content like this from Steve Souders.
You could load your UI via a web service or you could construct it locally.
If you don't want to use JSONP style requests, you'll need to investigate enabling CORS.
You could use an iframe and PostMessage to show some UI without needing to do complex wrapping/remapping of the various application dependencies that you have. PostMessage would allow you to send messages to tell the listening iFrame "what to do" at any given point, while the code that is running in the host page could move/manipulate the iframe into position. A number of popular embedded APIs have used this technique over the years. I think DropBox was using it for example.
I am tinkering around with jQuery and am finding it very useful and almost exciting.
As of now, I am referencing the jQuery script via Google's CDN and I store plugins I use locally in a static/scripts directory.
Naturally, each page has its own individual implementation of components that are required for the features it currently offers. I.E. the main page has the Twitter plugin whereas the login page has form validation logic and password strength metering. However, certain components (navigation bar) for example use the same script across multiple pages.
Admittedly so, I am not a fan of putting javascript code in the header of a page, but I rather prefer to have it in an external file (for caching, re-usability, and optimization purposes).
My question is, what is the preferred route for organizing the external files. I wanted to try and keep it to one javascript file for the entire site to reduce IO requests. However, I am not sure how to implement document ready functions on a conditional per page bases.
$(document).ready(function () { ... }
Is there some way to reference a page by some method (preferably id based and not a url conditional).
Thank you in advance for your time!
You should try REQUIRE JS.
This will allow you to load only those plugins the pages where you need them, and unload them again if they are not needed anymore.
Then again, it might be overkill. It really depends on the size of your project.
Paul Irish:
http://paulirish.com/2009/markup-based-unobtrusive-comprehensive-dom-ready-execution/
This will allow you to block your scripts by body class/ID and execute them automatically.
First you might want to use YUI Compressor or some other JS compressing tool. Then perhaps creating a resource file (resx) for your JavaScript is the way to go. Then just reference the resource within your code. This is the approach Telerik took for their RadControl ASP.NET AJAX control framework.
When you have a small HTML template, wouldn't it be nice to have the CSS and Javascript that relate to it (binding of events, etc.) in the same file right next to the HTML?
You could just put them in and tags, but normally you don't want to do this, because when you render the template many times you'll end up multiplying the code over and over again in the DOM. Besides, every respecting webdeveloper wants their CSS and Javasciprt in separate files.
But it's actually pretty simple to implement a system that goes through all your templates, removes all the tags with their contents and puts them into one big .css file and then the with contents to .js file, so that you can load them from separate files, and finally the tempalates are left with only HTML in them.
I'v done this and i'm still learning with the best practices on how to use it (eg. what parts of Javasript do you want to put there?), but it feels like the way i'd always want to develop web apps. So i'm wondering if there are any systems that use the same method.
Parsing HTML to remove duplicate tags as a standard practice seems wrong. Separating content, style and behavior should be a first class priority in any case. Why combine something just to rip it apart again? Imagine your CSS differs slightly among files. How does your parser know which one to keep?
IMO a proper templating approach for Javascript has a main HTML file, which is loaded using a HTTP request, which again links the CSS and JS for the rest of the application. This first file can as well link JS template files (like e.g. .jst) or these are loaded later on demand using an AJAX request. Nevertheless are these templates usually only containing structure, content comes from e.g. a JS model using a JSON connection to some kind of storage, "styling" is provided by the previously loaded CSS files.
Related: backbone.js and sammy.js
I am a javascript newbie. I am trying to write a requirements document, and need some help describing what I am looking for. We want our application to generate a javascript snippet like this:
<script src="http://www.jotform.com/jsform/10511502633"></script>
This will load a web form.
So my question is:
- How does a single script load an entire web form? Is this a JSON?
- What is this called? Is this a cross browser javascript?
- Can anyone point me in the direction of learning more about what this is?
Thank you for your help!
The javascript file is just hosted on an external site. It appears to be dynamically generated, so feel free to use some fancy words ;) But basically, you just include it here, as if it was on your own site.
You could say "The application will generate the required script-tags to include dynamically generated javascript file from an external, third-party site".
Offcourse you need to take special cautions for cases when the include won't work, because the other site is not reachable (site is down, DNS does not work, file is moved on other webserver, your application is on an intranet/behind a proxy/firewall...). Why can't you copy their file and mirror it locally? Or use a reliable Content Delivery Network, like Google or Amazon.
There are many names for this type of inclusion. The most common being widget.
What does it actually do:
take an id of some sort as parameter
use the id to fetch some specific data (most likely from a database)
generate some js and html based on the id/data
usually this involves iframes of some sort.
To use a script rather than an html iframe has multiple advantages
you can change what is actually delivered to the users browsers without changing the include
you can resize the iframe to fit certain predefined sizes
you can inject the necessary things into the page the widget is included (of course you need to make sure this is sanctioned)
We use this all the time and we never regreted it.
If you don't want to build the widget infrastructure yourself you can always use one of the widget providers like widgetbox:
http://www.widgetbox.com/widgets/make/
With those you are up and running in no time.
This is typically called a script include.
Google have lots of these types of items, and even they call them by many names,
widgets, custom javascript, snippets, custom code, etc. It really depending on who you are writing for... I would go with "cross platform embeddable javascript code" meaning that it would need to load all its dependancies. Also specify which browsers need to be supported and what should happen is the user has javascript turned off.
EDIT :
Actually since we are talking unique IDs, you will need 2 parts probably, the user/site unique "cross platform embeddable javascript code" and whatever serverside code to support it. Basically this is an API that is accessed using your own javascript widget. Feel free you point to examples in your requirements document, programmers love examples.