I have a Rails4 app which uses MathJax. I use MathJax CDN by placing the following line in the <head> section of my app/views/layouts/application.html.erb file:
<script type="text/javascript" src="path-to-mathjax/MathJax.js?config=TeX-AMS-MML_HTMLorMML"></script>
More information on: http://docs.mathjax.org/en/latest/start.html#mathjax-cdn
Because of Turbolinks, MathJax loads only on the homepage and won't load on other pages unless I refresh the page (which is not desirable). Instead I want MathJax to load only on /Math/New and Physics/Show pages. What should I do? (I don't want to deactivate turbolinks)
Thanks a lot for your help.
I was also struggling with the same issue since last few days. Finally figured out the way to solve this. Here is the explaination for the same:
If you are writing a dynamic web page where content containing mathematics may appear after MathJax has already typeset the rest of the page, then you will need to tell MathJax to look for mathematics in the page again when that new content is produced. To do that, you need to use the MathJax.Hub.Typeset() method. This will cause the preprocessors (if any were loaded) to run over the page again, and then MathJax will look for unprocessed mathematics on the page and typeset it, leaving unchanged any math that has already been typeset.
So the simplest solution is to add the following in app/views/layouts/application.html.erb file:
<script>
MathJax.Hub.Typeset();
</script>
Don't add this in head section. Add it after closing the body tag.
You can add data-no-turbolink only for that link to make it work as regular link, take a look at https://github.com/rails/turbolinks/#opting-out-of-turbolinks
Three great solutions can be found here: http://reed.github.io/turbolinks-compatibility/mathjax.html
Related
I am using gatsby js to build my static amp page and you can see the final html output in the search console. You can see that the generated html passes amp validation. That test passes because I copy and pasted the generated html.
However the website fails because on page load the official amp script <script async src="https://cdn.ampproject.org/v0.js"></script> adds ineligible tags. If I remove the script, the html stays the same. There are other scripts but I am 99% sure it's ^ one because I tried removing them one by one.
The script adds things like amp-version i-amphtml-sizer in the css and changes other things on the page. I am not sure why it would add these tags because v0.js is recommended by amp.
You can see the failing page here.
https://search.google.com/test/amp?id=aClwacaTtbw5q7-Dm3glPg&skip_amp_follow=true
If someone can point me to the original amp v0.js I will be truly grateful. The CDN version is uglified+transpiled and it's really hard to debug my issue.
This was caused by amp cache. I had to follow this guide to invalidate the cache for all my amp pages.
https://developers.google.com/amp/cache/update-cache.
I have Google Content Experiments code which looks like this:
<script type="text/javascript">
function utmx_section(){}function utmx(){}(function(){var
k='1234566789-0',d=document,l=d.location,c=d.cookie;
if(l.search.indexOf('utm_expid='+k)>0)return;
function f(n){if(c){var i=c.indexOf(n+'=');if(i>-1){var j=c.
indexOf(';',i);return escape(c.substring(i+n.length+1,j<0?c.
length:j))}}}var x=f('__utmx'),xx=f('__utmxx'),h=l.hash;d.write(
'<sc'+'ript src="'+'http'+(l.protocol=='https:'?'s://ssl':
'://www')+'.google-analytics.com/ga_exp.js?'+'utmxkey='+k+
'&utmx='+(x?x:'')+'&utmxx='+(xx?xx:'')+'&utmxtime='+new Date().
valueOf()+(h?'&utmxhash='+escape(h.substr(1)):'')+
'" type="text/javascript" charset="utf-8"><\/sc'+'ript>')})();
</script>
<script type="text/javascript">utmx('url','A/B');</script>
I need to add it to an Angular app, but only to a single page. The problem is that it uses document.write() which makes the page go blank if added dynamically. If I add it statically to the main index.html it will load on all pages, not just the one I want. Is there a way around this? I believe it could be done with server-side rendering, but I don't have it set up right now, and doing it just for this little script seems like an overkill.
You should use content experiments api instead https://developers.google.com/analytics/solutions/experiments-client-side
But, it doesn't work well with Single Page Apps, yet...
I am little new to web development and when I was searching internet about other topics, I have seen many people has put popular JS Libraries in Different Places of their websites.
eg: Inserting JS Libraries on the Very Beginning or Start of the <head> </head> section. (Before loading any JS Code or a CSS File)
eg: Inserting JS Libraries on the End of the <head> </head> section. (After loading all JS Codes and CSS Files)
eg: Inserting JS Libraries on the End of the <body> </body> section. (After loading all JS Codes, Texts, Images, Videos, CSS Files etc...)
So my question is this.
What is the best practice for inserting (where) following JS Libraries, Plugins and CSS Style Sheets to a web page for the most faster loading times and other advantages? - Please mention the reason -
JQuery and it's Plugins
Bootstrap 3.js
Modernizr.js
Angular.js
And another widely used JS Libraries which I couldn't mention here...
Normalize.css
reset.css
bootstrap.css + more
Thank You..!
There is no so called "standard" method. The choice of where to put the lines boils down to one question: When will I need the library?
You see, web files loads line by line, let's take the following as an example of what I mean:
<script>
document.getElementById("target").innerHTML = "changed"
</script>
<p id="target">unchanged</p>
#target isn't altered because the script was loaded before the element did. Web files loads procedurally. When the line of JavaScript is loaded. It is executed immediately, but the target element isn't. So it couldn't change the element.
Even with jQuery, there is the same problem:
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<script>
$("#target").text("changed");
</script>
<p id="target">unchanged</p>
Therefore, we often use $(function(){}).
Back to the loading problem
People who put their <script> tags or <link> tags in the body (in front) or in the head, wanted to execute the script immediately, sometimes they won't use $(function()) or document.onload
People who put their <script> tags or <link> tags in the body (in the end) wanted to ensure all elements are loaded then execute the script or load CSS.
Conclusion
You should load independent resources such as jQuery first, then load dependent resources such as jQuery plugins. Then you try to decide when you want the resources to start loading, then put the lines in places.
You should put CSS links in the <head> tag because you don't want visitors seeing unstyled content before loading the CSS files.
If you can't decide or don't care about the time, put every <script> and <style> tags in the <head>.
Here is another post you might be interested in: Load and execution sequence of a web page?
CSS can added inside header tag & but put all JS Libraries and custom files just before closing closing body tag
<body>
//other tags
<script> All Scripts here </script>
</body>
By doing so you wont have to check if DOM content has loaded.
It decrease page loading time.Otherwise a js need to be completely loaded before DOM loading.
It also makes sure that all events are attached properly to DOM element.
I think this address all your concern specially the third one
CSS Sheets go in the < head >. The order of the CSS files matter so libraries should be put in first then you can put in the specific ones you have.
Javascript links go in the < body > but place them at the very end. That way your HTML content loads first then the JS loads and it will recognize all your selections. It is more efficient to do it this way.
The most important thing to note when placing your css and script tags is that the order you place them determines the order they are loaded in and if style or code is loaded later it over writes the code written before. So if you have css styling that assigns different styles to the same attributes of the same element then it is the one loaded later that takes effect. And with script tags it's important to remember that for dependency reasons. You should load the dependencies first so that they are there for the other scripts to use. Aside from that normally css tags are in the head and script tags at the bottom of your body element
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().
I have partial control of a web page where by I can enter snippets of code at various places, but I cannot remove any preexisting code.
There is a script reference midway through the page
<script src="/unwanted.js" type="text/javascript"></script>
but I do not want the script to load. I cannot access the unwanted.js file. Is there anyway I can use javascript executing above this refernce to cause the unwanted.js file not to load?
Edit: To answer the comments asking what and why:
I'm setting up a Stack Exchange site and the WMD* js file loads halfway down the page. SE will allow you to insert HTML in various parts of the page - so you can have your custom header and footer etc. I want to override the standard WMD code with my own version of it.
I can get around the problem by just loading javascript after the original WMD script loads and replacing the functions with my own - but it would be nice not to have such a large chunk of JS load needlessly.
*WMD = the mark down editor used here at SO, and on the SE sites.
In short, you can't. Even if there is a hack, it would heavily depend on the way browsers parse the HTML and load the scripts and hence wouldn't be compatible with all browsers.
Please tell us exactly what you can and cannot do, and (preferably; this sounds fascinating) why.
If you can, try inserting <!-- before the script include and --> afterwards to comment it out.
Alternatively, look through the script file and see if there's any way that you could break it or nullify its effects. (this would depend entirely on the script itself; if you want more specific advice, please post more details, or preferably, the script itself.
Could you start an HTML comment above it and end below it in another block?
What does the contents of unwanted.js look like?
You can remove a script from the DOM after it is called by using something simple such as:
s = document.getElementById ("my_script");
s.parentNode.removeChild(s);
This will stop all functions of the script but will not take it out of user's cache. However like you wanted it can't be used.
Basically you can't unless you have access to the page content before you render it.
If you can manipulate the HTML before you send it off to the browser, you can write a regular expression that will match the desired piece of code, and remove it.