Run javascript script in Angular 2/4 app included through HTML injection - javascript

I'm having a problem with scripts in Angular 4. Let me explain: I'm building an Angular app that will be included in a greater web application. So my app is only one among other apps inside this greater web application. In my app I need to include some HTML code representing common areas of this web application. They would be the head, header, menu and footer of the app. My app would be placed in the remaining space. Thus, I retrieve these HTML codes, turn them into SafeValue by bypassing sanitizing and include them by using the innerHTML property of some divs. After that I can see these HTMLs rendered with styling and all.
So this is the context. The problem is that the scripts in these HTMLs don't run. Even though they are not removed (you can examine the page's HTML and see the scripts there), they do not run. I need them to run as they are needed to perform some important tasks such as to fill the menu with links, animate menu expansion and god knows what else.
I have already tried to include these HTMLs in the index.html using the document DOM object to replace a div I've put in index.html as a placeholder, but I've had the same problem: it renders, but the scripts don't run. Something interesting is that if I put the script tag that is not running in the index.html directly (hardcoded, not dynamically) it works.
So, the scripts would have the following form:
<script type="text/javascript" src="//some_external_source"></script>
Only a remark: I have no control over these common HTMLs that I receive. I just receive them and have to use them for the sake of visual identity of the web application.
Sorry if it has already been answered. I have been looking for an answer for days now and I still didn't found one (I did found something similar for AngularJS though), so I posted.

This is not the way angular 2 intended such problems to be solved, if you want to divide your app into separate parts like: content, header, footer you should probably take a look at named router-outlets, or transcludion.
But if you want to do this your way, then do this:
#Component({.your metadata..})
export class SomeComponent{
constructor (private domSanitizer:DomSanitizer){
this.domSanitizer.bypassSecurityTrustScript(yourScript);
}
}

Related

CSS Generic vs Page Specific loading

I need some advice on CSS placements for the sake of website load times
I read that it's best to have 'critical CSS' in the head and the rest can be placed in their respective page's body via the tag.
Is it good practice if I loaded all the CSS or at least the 'Generic' styles that many pages share while I kept page specific styles in a tag in the page's body?
One side question, some of my pages use jQuery, should I only load that at the bottom of those pages or leave it in the template head?
I tried both and the site loads just fine, but I know under the hood results may vary. I'm not sure how to even check. I tried websites that test a website's load performance and I got mixed results. So I'm not sure how to optimize my website's performance.
Usually all CSS files are called in the head, one thing you can do to improve performance is to modularize, let's say that you have the global styles in one file called global.css and it contains your font specs, global components used in all pages such as navbar, footer, layouts, etc... And in another file you can only put the styles regarding your specified page such as contact section that's another page called contact.css and there you can have overrides to global file and specific styles that you only use in this page.
This way you can serve less heavy files regarding the page that user's requiring.
Regarding you jQuery question I suggest that don't load jQuery library if you're not using it, it's useless. Only load it in the pages that you're using the library. Hope it helps!

Where to put script references for widgets (partial page)

Working on MVC5 asp.net website.
I have a "dashboard" page that allows the user to place pre-defined "widgets" on the page. These widgets are simply MVC 5 partial pages (Razor). I really wanted each widget to be "self-contained" so all references, scripts, etc... are within the widget's cshtml file. BUT, the main "dashboard" page also needs certain references to jQuery, bootstrap, etc...
Of course, doing this, I could encounter conflicts, duplicate references (one from main page, one from widget), etc....
Question: What is the preferred method for this scenario? Should references like jQuery and bootstrap be JUST on the main "dashboard" page? What about javascript or jQuery code that is in the widget itself? Should this remain in the widget? If so, will I encounter the issue where it doesn't have jQuery defined (because it's in the parent page), etc...?
Any thoughts on this would be appreciated?
Thanks!
**** UPDATE ****
TO further clarify: If I put the scripts, references, etc (specific to the widget) at the bottom of the widget, then when the partial page is rendered on the main page, the scripts, etc.. are not rendered at the bottom of the main page. This causes my code to act funny because of the order that things are rendered. This is one reason I ask this question. Hope this makes sense. Thanks.
Put the script code and references that are global to the application , that are used everywhere and that are not specific to a widget in the most outer page.
What i would do, is i would bundle all my script references in one place and add that bundle link to the dashboard page, this makes your code cleaner and your page will have less external references thus a better client side performance.

why angular js not loads instantly, it takes time to load

This is the demo is used to build my project:
https://material.angularjs.org/HEAD/demo/
I changed a lot of menus but the page heading and the data stayed the same. I face the same problem as in the demo. The browser does not render the page instantly but it takes some time in the beginning before the elements content is shown.
You can use ngCloak to prevent that. Put ng-cloak on your body tag and follow the documentation.
When this css rule is loaded by the browser, all html elements (including their children) that are tagged with the ngCloak directive are hidden. When Angular encounters this directive during the compilation of the template it deletes the ngCloak element attribute, making the compiled element visible.
For the best result, the angular.js script must be loaded in the head section of the html document; alternatively, the css rule above must be included in the external stylesheet of the application.
Your question isn't clear! But from what u r facing seems, your one/more service call(s) taking time to fetch data intially which might be making your application slow. Go to network in dev tools and check which service is taking lots of time!

Multiple pages on a single page

I am using backbone.js and building a single page application, inspired by trello.com ..
I want to know how you show many pages on top of the original page. As in how you architect it.
How do you use Backbone routers to achieve this?
For example in trello
Basepage
And then now on top of the base page you have dynamic content
like a cards detail
like a boards details
How could i architecture something like this?
I've done a couple of approaches so far in projects with 50+ pages and they both scaled well. I did not use backbone.js but the approaches are straight forward and do not require a framework to learn other than I used jQuery for selectors.
Both of them have in common creating a single overlay window that you can pull in content into the window. I wrote mine from scratch but you could easily use jQuery UI dialog. The two approaches only differ in how the content is pulled. Also, using the information on the link is all you should need to pull in the "module" or overlay content as your rule. Do not need tons of scripts loaded in to start your app. Have the modules pull in the behavior for you.
Option 1) Use the jQuery load method to pull content from stand-alone web pages by using a placeholder variable like so:
var $ph = $('<div />');
$ph.load(URL); // loads gui of remote URL + executes any script that URL has
The $ph var now contains all the GUI loaded in from the external URL so you can use selector on it to extract the particular HTML and place it into your DOM or overlay as you need.
Here is an example of the stand-alone HTML output:
<div class="module">
<a class="link">click me</a>
</div>
<script>
(function(){
// put any private vars here
$('.module .link').click(function(){
// do something
});
})();
</script>
If you remove() or destroy the dom inside the overlay through jQuery, it will automatically remove all the events directly assigned aka "bind" and "unbind" them but using "live" or "delegate" you will need to worry about "die" and "undelegate" etc. just doing die('.namespace').live('click.namespace') will ensure is cleaned.
Here is an example of this on one of my websites -> http://www.kitgui.com/docs
But the better example is within the customer section as the docs is fairly simple using hash history.
2) Using an iframe inside your overlay and assigning it a URL.
This is the easiest option but is a little slower because each page called has to have a full standalone behavior and dependencies with the iframe. Also you must worry about sizing the frame etc. unless you have a fixed overlay window.
You must have a loader overlay your iframe while its loading then have the iframe talk the parent to tell it its done loading and hide the loader.
I did this for several sites but one of them is a site in development you can see here to get the code ->
http://dev.zipstory.com (sign in and go to my zipstory and click "group" settings etc to see this, just view source to see how I did this as its all there)
The thing about iframes is you should write some code on the parent that accepts standard messages from the iframe that you agree on as a typical set of behavior such as notifying its done loading or passing messages to update something on the parent etc. This can be added on the fly and refactored as you need as long as your aim is KISS approach.
Each of the 'dynamic content' pages should be a template (underscore.js gives you _.template()) rendered by a backbone view. The main page needs to have events that initialize new views and render the templates. Look at the todos app (http://documentcloud.github.com/backbone/docs/todos.html) to get a basic idea about the flow of a backbone app.

Dynamically adding and removing javascript/css with Jquery (or other library)

I am trying to compare having a 1 page app with clientside routing to having a asp mvc app which just routes to html files, to see which is more appropriate for my current project. As I have no need for any Asp Mvc features its all javascript/html which communicates with a web service.
However one problem I can forsee with the one page app is that my site isnt really 1 page, so I would be having to have on main index.html which contained all shared resources. Then dynamically load in new pages based on the hashbang and add in any required scripts and css. This doesn't seem to hard as Jquery I believe provides a .load() method or something similar to get external resources... my problem though is getting rid of them once I am done...
Is there any way to do this, so you target ONLY certain script/link tags, can you give them Ids or something?
Any help on this would be great...
== EDIT ==
Added a simple example to show what I mean:
<!-- Script already in page -->
<script type="text/javascript" src="scripts/script1.js"></script>
<!-- Dynamically added script -->
<script type="text/javascript">
// some javascript
</script>
How can you tell which ones you should remove? If you could apply an id or uniqueness to each script then it may be ok, but thats what i am getting at with this question.
There are zero benefits to "removing resources." When a script has been loaded, removing the script tag from the page later has no purpose--it won't improve your browser performance at all, nor will it harm it to keep the files around.
Simply add your resources as needed and write your code such that it won't execute erroneously.
I'm not shre i understand why you would like to do that but link element (for css) and script (for js) are elements like any other and they can be deleted with remove().

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