JavaScript: How should I generate a lot of HTML? [duplicate] - javascript

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Is there a best practice for generating html with javascript
I want to generate large parts of a website with JavaScript.
The straightforward way is to form one large string containing all the HTML:
'<div>'
+ '<span>some text</span>'
+ '<form>'
+ '<input type="text" />'
...
But this gets quite annoying when one has to write a few hundred lines in this style. And the pain when such code has to be changed later on...
Can you think of an easier way?

Create snippets as templates, put them into an invisible <div>:
<div style="display: none">
<div id="template1">
<h2 class="header_identifyingClass">Hello from template</h2>
</div>
<div id="template2">
<span class="content">Blah blah</span>
</div>
</div>
Then find it,
document.getElementById("template1");
fill it's internal values, e.g. find inside elements by XPath or jQuery and fill them e.g. using element.innerHTML = "Hello from new value", and move or copy it to the visible part of DOM.
Create multiple templates and copy it multiple times to generate many.
Don't forget to change the ID for copies to keep it working.
PS: I think I used this approach in the code of JUnitDiff project. But it's buried in XSLT which serves another purpose.

By far the best way to do this is to use some kind of JavaScript templating system. The reason why this is better than hiding HTML with CSS is that if (for example) someone has CSS disabled, they'll be able to see your templates, which is obviously not ideal.
With a templating system, you can put the templates in a <script> tag, meaning that they're totally hidden from everything except JavaScript.
My favourite is the jQuery templating system, mostly because jQuery is so ubiquitous these days. You can get it from here: http://api.jquery.com/category/plugins/templates/
An example (taken from the jQuery docs):
<ul id="movieList"></ul>
<!-- the template is in this script tag -->
<script id="movieTemplate" type="text/x-jquery-tmpl">
<li><b>${Name}</b> (${ReleaseYear})</li>
</script>
<!-- this script will fill out the template with the values you assign -->
<script type="text/javascript">
var movies = [
{ Name: "The Red Violin", ReleaseYear: "1998" },
{ Name: "Eyes Wide Shut", ReleaseYear: "1999" },
{ Name: "The Inheritance", ReleaseYear: "1976" }
];
// Render the template with the movies data and insert
// the rendered HTML under the "movieList" element
$( "#movieTemplate" ).tmpl( movies )
.appendTo( "#movieList" );
</script>
It's a simple example, but you could put all of the HTML you'd like to generate in the <script>, making it much more flexible (use the same HTML snippet for various jobs, just fill out the gaps), or even use many templates to build up a larger HTML snippet.

Use a dialect of JavaScript such as CoffeeScript. It has heredocs:
'''
<div>
<span>some text</span>
<form>
<input type="text" />
'''
If you need to throw in an occasional expression, you can use interpolations:
"""
<title>#{title}</title>
"""

If it's static content that you're just adding to the page on a javascript event, you could consider simply having it in your main HTML page all along, but style with display:none;.
Then it's just a case of changing it's style to make it appear on the page. Much easier.
Even if it's dynamic, you could use this technique: have the shell HTML content there hidden in your page, and populate the dynamic bits before making it visible.
hope that helps.

Related

How to automate selecting certain codes in an html?

Hi I have a question about automating selecting certain content in an HTML. So if we save an webpage as html only, then we'll get HTML codes along with other stylesheets and javascript codes. However, I only want to extract the HTML codes between <div class='post-content' itemprop='articleBody'>and</div> and then create a new HTML file that has the extracted HTML codes. Is there a possible way to do it? Example codes are down below:
<html>
<script src='.....'>
</script>
<style>
...
</style>
<div class='header-outer'>
<div class='header-title'>
<div class='post-content' itemprop='articleBody'>
<p>content we want</p>
</div>
</div></div>
<div class='footer'>
</div>
</html>
While I'm typing, I'm thinking about javascript, which seems to be able to manipulate HTML DOM elements..Is Ruby able to do that? Can I generate a new clean html that only contains content between <div class='post-content' itemprop='articleBody'>and</div> by using javascript or Ruby? However, as for how to write the actual code, I don't have a clue.
So anybody has any idea about it? Thank you so much!
I'm not quite sure what you're asking, but I'll take a crack at it.
Can Ruby modify the DOM on a webpage?
Short answer, no. Browsers don't know how to run Ruby. They do know how to run javascript, so that's what usually used for real-time DOM manipulation.
Can I generate a new clean html
Yes? At the end of the day, HTML is just a specifically formatted string. If you want to download the source from that page and find everything in the <div class='post-content' itemprop='articleBody'> tag, there are a couple of ways to go about that. The best is probably the nokogiri gem, which is a ruby HTML parser. You'll be able to feed it a string (from a file or otherwise) that represents the old page and strip out what you want. Doing that would look something like this:
require 'nokogiri'
page = Nokogiri::HTML(open("https://googleblog.blogspot.com"))
# finds the first child of the <div class="post-content"> element
text = page.css('.post-content')[0].text
I believe that gives you the text you're looking for. More detailed nokogiri instructions can be found here.
You want to use a regular expression. For example:
//The "m" means multi-line
var regEx = /<div class='post-content' itemprop='articleBody'>([\s\S]*?)<\/div>/m;
//The content (you'll put the javascript at the bottom
var bodyCode = document.body.innerHTML;
var match = bodyCode.match( regEx );
//Prints to the console
console.dir( match );
You can see this in action here: https://regex101.com/r/kJ5kW6/1

Formatting dynamically formed HTML elements created after Script is run

So this is actually a very tricky concept to portray so here is my attempt.
I am utilizing an HTML form template in LANDesk Service Desk - tool is irrelevant but important to note that there is back-end code that I cannot touch that is generating HTML.
So basically, the tool is pulling data from a back-end database containing a list of objects. It then inputs this data into an HTML form template that I have created using variables as placeholders for the objects. The HTML is then built on the fly with however many objects are in the database. Thus, I have no way of accessing the head - (which means native JS, and inline CSS).
My template looks like this...
<div class="my-template">
<a class="my-template my-link">My Link</a>
</div>
<script>
var myLinks = document.getElementsByClassName('my-link');
for (var i = 0 ; i < myLinks.length ; i++) {
myLinks[i].style.display = "none";
}
</script>
When I view the source on the loaded page it looks something like this...
<body>
<!--misc. page stuff-->
<!--First Item-->
<div class="auto-create">
<div class="my-template">
<a class="my-template my-link">My-Link</a>
</div>
</div>
<!--Second Item-->
<div class="auto-create">
<div class="my-template">
<a class="my-template my-link">My-Link</a>
</div>
</div>
</body>
All of the elements are formatted the way I want them to be...besides the last element on each page. I have determined that this is because each time the tool is running the object through the template, it is running the script. The issue is, there is a stupid default button that they place at the bottom of each object that is broken. (This is why I have the script changing the style to display: none..should have mentioned this earlier). Basically I want to delay the execution of the script until not only the object has been run through the template...but the entire page has loaded...but I can't seem to get the last button to go away.
I know that this is a lot of poorly written words trying to form an explanation, but I really think this is impossible...but I am convinced there has to be a way. (Also, the company isn't providing us with any help in finding a workaround, so I had to basically MacGyver this one

template insertion in a editor

Describing a scenario:
I am going through the code mentioned below.B asically I am trying to figure out how to program so that
when a user clicks on "Use Template" button , it gets inserted into an editor.
Page 1:
There are lot of templates present
When a user clicks on the "Use Template" button on , it gets inserted into an editor that is present in
the next page (Page 2).
Please find the code snippet below for the first two templates I am going through:
<div id="templatesWrap">
<div class="template" data-templatelocation="templateone" data-templatename="Template ONE" data-templateid="" >
<div class="templateContainer">
<span>
<a href="https://app.abc.com/pqr/core/compose/message/create?token=c1564e8e3cd11bc4t546b587jan31&sMessageTemplateId=templateone&sHubId=&goalComplete=200" title="Use Template">
<img class="thumbnail" src="templatefiles/thumbnail_010.jpg" alt="templateone">
</a>
</span>
<div class="templateName">Template ONE</div>
<p>
Use Template
</p>
</div>
</div>
<div class="template" data-templatelocation="templatetwo" data-templatename="Template TWO" data-templateid="" >
<div class="templateContainer">
<span>
<a href="https://app.abc.com/pqr/core/compose/message/create?token=c1564e8e3cd11bc4t546b587jan31&sMessageTemplateId=templatetwo&sHubId=&goalComplete=200" title="Use Template">
<img class="thumbnail" src="templatefiles/thumbnail_011.jpg" alt="templatetwo">
</a>
</span>
<div class="templateName">Template TWO</div>
<p>
Use Template
</p>
</div>
</div>
And so on ....
How does the link "https://app.abc.com/pqr/core/compose/message/create?token=c1564e8e3cd11bc4t546b587jan31&sMessageTemplateId=templatetwo&sHubId=&goalComplete=200" is inserting the template into the editor which is located on the next page? I haven't understood the token part and lot's of ID's present in the link
which I think are thereason behind inserting the template.
Has anyone come across such link before? Please advise.
Thanks
MORE CLARIFICATIONS:
Thanks for your answer.It did help me somewhat. I have few more questions:
Basically, I am using TinyMCE 4.0.8 version as my editor. The templates, I am using are from here:
https://github.com/mailchimp/email-blueprints/blob/master/templates/2col-1-2-leftsidebar.html
Some questions based on "Tivie" answer.
1) As you can see in the code for "2col-1-2-leftsidebar.html " it's not defined inside <div> tags unlike you defined it in <div> tags. Do you think that I can still
use it using "2col-1-2-leftsidebar.html " name?
2)I believe,for explanation purpose, you have included
`"<div contenteditable="true" id="myEditor">replaced stuff</div>`
and
<button id="btn">Load TPL</button>
<script>
$("#btn").click(function() {
$("#myEditor").load("template.html");
});
</script>
in the same page. Am I right? ( I understand you were trying to make an educated guess here, hence
just asking :) )
In my case, I have a separate page, where I have written code for buttons just like you wrote in editor.html like the following:
<button id="btn">Load TPL</button>. My button is defined inside <div class="templateContainer">.
Also, my templates are defined in a separate folder. So, I will have to grab the content(HTML Template), from
that folder and then insert into TinyMCE 4.08 editor. (Looks like two step process). Could you elaborate
on how should I proceed here?
More Question As of Dec 27
I have modifier my code for the template as follows:
<div class="templateName">Template ONE</div>
<p>
Use Template
</p>
Please note, I have added an additional id attribute for the following purpose.
If I go by the answer mentioned in the Tivia's post, is the following correct?
<script>
$("#temp1").click(function() {
$("#sTextBody").load("FolderURL/template.html");
});
</script>
My editor is defined like the following on Page 2 (Editor Page).
<div class="field">
<textarea id="sTextBody" name="sTextBody" style="width:948px; max-width:948px; height: 70%"></textarea>
</div>
I am confused, like, the script tag I have defined is in Page 1 where I have defined all the template related code
and the Page 2(Editor) page is a different page. It's simply taking me to Editor page (Page 2) and hence not working.
Please advise where I am wrong.
Thanks
MORE QUESTIONS AS of Jan 2
The problem Iam facing is as follows. Basically, for first template , I have the following code.
Code Snippet #1 where "Use "Template" button is present:
<div class="templateName">Template ONE</div>
<p>
Use Template
</p>
And the function suggested in the answer is as follows:
Code Snippet #2 where Editor is present:
<script>
$("#temp1").click(function() {
$("#sTextBody").load("FolderURL/template.html");
});
</script>
Since, I believe I first need to reach to that page after user clicks on "Use Template" button, where the editor is located, I have defined Code Snippet #1 on Page 1 and have defined the Code Snippet #2 and <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script> as the very first two script tags in the Page 2 ( Editor Page). But still when I click on "User Template" button on Page 1, it's just letting me to next page and not loading the template into the editor.
Am I doing something wrong here? Please advise.
P.S. The problem I feel is somehow the click function on Page 2 is not getting activated with the temp1 id button mentioned on Page 1.
Thanks
Well, one can only guess without having access to the page itself (and it's source code). I can, however, make an educated guess on how it works.
The URL params follows a pattern. First you have a token that is equal in all templates. This probably means the token does not have any relevance to the template mechanism itself. Maybe it's an authentication token or something. Not relevant though.
Then you have the template identification (templateOne, templateTwo, etc...) followed by a HubId that is empty. Lastly you have a goalComplete=200 which might correspond to the HTTP success code 200 (OK).
Based on this, my guess would be that they are probably using AJAX on the background, to fetch those templates from the server. Then, via JScript, those templates are inserted into the editor box itself.
Using JQuery, something like this is trivial. here's an example:
template.html
<div>
<h1>TEST</h1>
<span>This is a template</span>
</div>
editor.html
<!DOCTYPE HTML>
<html>
<head>
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script>
</head>
<body>
<div contenteditable="true" id="myEditor">
replaced stuff
</div>
<button id="btn">Load TPL</button>
<script>
$("#btn").click(function() {
$("#myEditor").load("template.html");
});
</script>
</body>
</html>
Edit:
1) Well, since those templates are quite complex and include CSS, you probably want to keep them separated from you editor page (or the template's CSS will mess up your page's css).
However, since you're using TinyMCE, it comes with a template manager built in, so you probably want to use that. Check this link here http://www.tinymce.com/wiki.php/Configuration:templates for documentation.
2) I think 1 answers your question but, just in case, my method above works for any page in any directory, provided it lives on the same domain. Example:
<script>
$("#btn").click(function() {
$("#myEditor").load("someDirectory/template.html");
});
</script>
I recomend you check this page for the specifics on using TinyMCE http://www.tinymce.com/wiki.php/Configuration:templates
EDIT2:
Let me explain the above code:
$("#btn").click(function() { });
This basically tells the browser to run the code inside the brackets when you click the element with an id="btn"
$("#myEditor").load("someDirectory/template.html");
This is an AJAX request (check the documentation here). It grabs the contents of someDirectory/template.html and places them inside the element whose id="myEditor"

Updating the content of a div with javascript

Rather than trying to create tons of different pages on my website, I'm trying to update the content of a single div when different items in the navbar are click to update the maint div content. I tried to find a simple example using Javascript:
<script type="text/javascript">
function ReplaceContentInContainer(id,content) {
var container = document.getElementById(id);
container.innerHTML = content;
}
</script>
<div id="example1div" style="border-style:solid; padding:10px; text-align:center;">
I will be replaced when you click.
</div>
<a href="javascript:ReplaceContentInContainer('example1div', '<img src='2.jpg'>' )">
Click me to replace the content in the container.
</a>
This works just fine when I only try and update text, but when I put an img tag in there, as you can see, it stops working.
Either
1) what is the problem with how I am trying to do it?
or 2) What is a better/easier way to do it?
I'm not stuck on Javascript. jQuery would work too, as long as it is just as simple or easy. I want to create a function that will just let me pass in whatever HTML I want to update and insert it into the div tag and take out the 'old' HTML.
You just have some escaping issues:
ReplaceContentInContainer('example1div', '<img src='2.jpg'>')
^ ^
The inner ' need to be escaped, otherwise the JS engine will see ReplaceContentInContainer('example1div', '<img src=' plus some syntax errors resulting from the subsequent 2.jpg'>'). Change the call to (tip of the hat to cHao' answer concerning escaping the < and > in the HTML):
ReplaceContentInContainer('example1div', '<img src=\'2.jpg\'>')
A simple way to do this with jQuery would be to add an ID to your link (say, "idOfA"), then use the html() function (this is more cross-platform than using innerHTML):
<script type="text/javascript">
$('#idOfA').click(function() {
$('#example1div').html('<img src="2.jpg">');
});
</script>
First of all, don't put complex JavaScript code in href attributes. It's hard to read or to maintain. Use the <script> tag or put your JavaScript code in a separate file altogether.
Second, use jQuery. JavaScript is a strange beast: the principles underlying its patterns were not designed with modern-day web development in mind. jQuery gives you lots of power without miring you in JavaScript's oddities.
Third, if your goal is to avoid having to endlessly duplicate the same basic structure for all (or many) of your pages, consider using a templating system. Templating systems allow you to plug in specific content into scaffolds containing the common elements of your site. If it sounds complicated, it's because I haven't explained it well. Google it and you'll find lots of great resources.
Relying on JavaScript for navigation means your site won't be indexed properly by search engines and will be completely unusable to someone with JavaScript turned off. It is increasingly common--and acceptable--to rely on JavaScript for basic functionality. But your site should, at minimum, provide discrete pages with sensible and durable URLs.
Now, all that said, let's get to your question. Here's one way of implementing it in jQuery. It's not the snazziest, tightest implementation, but I tried to make something very readable:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>jQuery Example</title>
<style type="text/css" media="all">
/* all content divs should be hidden initially */
.content {
display: none;
}
/* make the navigation bar stand out a little */
#nav {
background: yellow;
padding: 10px;
}
</style>
</head>
<body>
<!-- navigation bar -->
<span id="nav">
about me |
copyright notice |
a story
</span>
<!-- content divs -->
<div class="content" id="about_me">
<p>I'm a <strong>web developer</strong>!</p>
</div>
<div class="content" id="copyright">
<p>This site is in the public domain.</p>
<p>You can do whatever you want with it!</p>
</div>
<div class="content" id="my_story">
<p>Once upon a time...</p>
</div>
<!-- jquery code -->
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.5.1/jquery.min.js"></script>
<script>
// Wait for the document to load
$(document).ready(function() {
// When one of our nav links is clicked on,
$('#nav a').click(function(e) {
div_to_activate = $(this).attr('href'); // Store its target
$('.content:visible').hide(); // Hide any visible div with the class "content"
$(div_to_activate).show(); // Show the target div
});
});
</script>
</body>
</html>
Ok, hope this helps! If jQuery looks attractive, consider starting with this tutorial.
Your main problem with your example (besides that innerHTML is not always supported) is that < and > can easily break HTML if they're not escaped. Use < and > instead. (Don't worry, they'll be decoded before the JS sees them.) You can use the same trick with quotes (use " instead of " to get around quote issues).

best way to inject html using javascript

I'm hoping that this isn't too subjective. I feel there is a definitive answer so here goes.
I want to create this html on the fly using JS (no libraries):
Play
Mute
<div id="progressBarOuter">
<div id="bytesLoaded"></div>
<div id="progressBar"></div>
</div>
<div id="currentTime">0:00</div>
<div id="totalTime">0:00</div>
using javascript. I know I can do this using createElement etc but it seems extremely long winded to do this for each element. Can anyone suggest a way to do this with more brevity.
I do not have access to a library in this project....so no jquery etc.
Keep your markup separate from your code:
You can embed the HTML snippets that you'll be using as hidden templates inside your HTML page and clone them on demand:
<style type="text/css">
#templates { display: none }
</style>
...
<script type="text/javascript">
var node = document.getElementById("tmp_audio").cloneNode(true);
node.id = ""; // Don't forget :)
// modify node contents with DOM manipulation
container.appendChild(node);
</script>
...
<div id="templates">
<div id="tmp_audio">
Play
Mute
<div class="progressBarOuter">
<div class="bytesLoaded"></div>
<div class="progressBar"></div>
</div>
<div class="currentTime">0:00</div>
<div class="totalTime">0:00</div>
</div>
</div>
Update: Note that I've converted the id attributes in the template to class attributes. This is to avoid having multiple elements on your page with the same ids. You probably don't even need the classes. You can access elements with:
node.getElementsByTagName("div")[4].innerHTML =
format(data.currentTime);
Alternatively, you can act on the HTML of the template:
<script type="text/javascript">
var tmp = document.getElementById("tmp_audio").innerHTML;
// modify template HTML with token replacement
container.innerHTML += tmp;
</script>
Shove the entire thing into a JS variable:
var html = 'Play';
html += 'Mute';
html += '<div id="progressBarOuter"><div id="bytesLoaded"></div><div id="progressBar"></div></div>';
html += '<div id="currentTime">0:00</div>';
html += '<div id="totalTime">0:00</div>';
Then:
document.getElementById("parentElement").innerHTML = html;
if you want theN:
document.getElementById("totalTime").innerHTML = "5:00";
You can use
<script type="text/javascript">
function appendHTML() {
var wrapper = document.createElement("div");
wrapper.innerHTML = '\
Play\
Mute\
<div id="progressBarOuter"> \
<div id="bytesLoaded"></div>\
<div id="progressBar"></div>\
</div>\
<div id="currentTime">0:00</div>\
<div id="totalTime">0:00</div>\
';
document.body.appendChild(wrapper);
}
</script>
If you live in 2019 and beyond read here.
With JavaScript es6 you can use string literals to create templates.
create a function that returns a string/template literal
function videoPlayerTemplate(data) {
return `
<h1>${data.header}</h1>
<p>${data.subheader}</p>
Play
Mute
<div id="progressBarOuter">
<div id="bytesLoaded"></div>
<div id="progressBar"></div>
</div>
<time id="currentTime">0:00</time>
<time id="totalTime">0:00</time>
`
}
Create a JSON object containing the data you want to display
var data = {
header: 'My video player',
subheader: 'Version 2 coming soon'
}
add that to whatever element you like
const videoplayer = videoPlayerTemplate(data);
document.getElementById('myRandomElement').insertAdjacentHTML("afterbegin", videoplayer);
You can read more about string literals here
edit: HTML import is now deprecated.
Now with Web Components you can inject HTML using an HTML import.
The syntax looks like this:
<link rel="import" href="component.html" >
This will just load the content of the html file in the href attribute inline in the order it appears. You can any valid html in the loaded file, so you can even load other scripts if you want.
To inject that from JavaScript you could do something of the likes of:
var importTag = document.createElement('link');
importTag.setAttribute('rel', 'import');
importTag.setAttribute('href', 'component.html');
document.body.appendChild(importTag);
At the time I am writing this, Chrome and Opera support HTML imports. You can see an up to date compatibility table here http://caniuse.com/#feat=imports
But don't worry about browsers not supporting it, you can use it in them anyway with the webcomponentsjs polyfill.
For more info about HTML imports check http://webcomponents.org/articles/introduction-to-html-imports/
If you don't need any validation for your syntax (which is what makes createElement() so nice) then you could always default to simply setting the innerHTML property of the element you want to insert your markup inside of.
Personally, I would stick with using createElement(). It is more verbose but there are far less things to worry about that way.
If performance is a concern, stay away from innerHTML. You should create the whole object tree using document.createElement() as many times as needed, including for nested elements.
Finally, append it to the document with one statement, not many statements.
In my informal testing over the years, this will give you the best performance (some browsers may differ).
If HTML is ever declared in a variable, it should be simple and for a very specific purpose. Usually, this is not the right approach.
here's 2 possible cases :
Your HTML is static
Your HTML is dynamic
solution 1
In this case, wrap your HTML in double quotes, make it a string and save it in a variable. then push it inside HTML, here's a demo 👇
HTML
<div id="test"></div>
JavaScript
let selector = document.querySelector("#test");
let demo_1 = "<div id='child'> hello and welcome</div>"
selector.innerHTML = demo_1;
solution 2
In this case, wrap your HTML in back ticks, make it a template literal and save it in a variable. then push it inside HTML,
here, you can use variables to change your content. here's a demo 👇
HTML
<div id="test"></div>
JavaScript
let selector = document.querySelector("#test");
let changes = 'hello and welcome'
let demo_1 = `<div id='child'>${changes}</div>`
selector.innerHTML = demo_1;
You can concatenate raw HTML strings (being careful to escape text and prevent XSS holes), or you can rewrite jQuery (or something similar)
I have a situation where I pass text into a third party library, but if my model isPrivate, I'd like to add an element to the text.
return { id: item.id, text: (item.isPrivate == true) ? "<i class=\"icon-lock\" title=\"Private group.\"></i> " + item.label : item.label };
This creates issues with the way the third party library builds up its markup.
This is never a good idea, but third party libraries are there so that we don't have to write everything ourselves. In a situation like this, you have to rely on passing markup though javascript.
When i find a proper solution to this, I will give you an update

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