Problem
I have a collection of images with linked captions on a page. I want them each to have identical HTML.
Typically, i copy and paste the HTML over and over for each item. The problem is, if i want to tweak the HTML, i have to do it for all of them. It's time-consuming, and there's risk of mistakes.
Quick and Dirty Templating
I'd like to write just one copy of the HTML, list the content items as plain text, and on page-render the HTML would get automatically repeated for each content-item.
HTML
<p><img src=IMAGE-URL>
<br>
<a target='_blank' href=LINK-URL>CAPTION</a></p>
Content List
IMAGE-URL, LINK-URL, CAPTION
/data/khang.jpg, https://khangssite.com, Khang Le
/data/sam.jpg, https://samssite.com, Sam Smith
/data/joy.jpg, https://joyssite.com, Joy Jones
/data/sue.jpg, https://suessite.com, Sue Sneed
/data/dog.jpg, https://dogssite.com, Brown Dog
/data/cat.jpg, https://catssite.com, Black Cat
Single Item
Ideally, i could put the plain-text content for a single item anywhere on a page, with some kind of identifier to indicate which HTML template to use (similar to classes with CSS).
TEMPLATE=MyTemplate1, IMAGE-URL=khang.jpg, LINK-URL=https://khangssite.com, CAPTION=Khang Le
Implementation
Templating systems are widely used, like Django and Smarty on the server side, and Mustache on the client side. This question seeks a simple, single-file template solution, without using external libs.
I want to achieve this without a framework, library, etc. I'd like to put the HTML and content-list in the same .html file.
Definitely no database. It should be quick and simple to set it up within a page, without installing or configuring additional services.
Ideally, i'd like to do this without javascript, but that's not a strict requirement. If there's javascript, it should be ignorant of the fieldnames. Ideally, very short and simple. No jquery please.
you mean Template literals (Template strings) ?
const arrData =
[ { img: '/data/khang.jpg', link: 'https://khangssite.com', txt: 'Khang Le' }
, { img: '/data/sam.jpg', link: 'https://samssite.com', txt: 'Sam Smith' }
, { img: '/data/joy.jpg', link: 'https://joyssite.com', txt: 'Joy Jones' }
, { img: '/data/sue.jpg', link: 'https://suessite.com', txt: 'Sue Sneed' }
, { img: '/data/dog.jpg', link: 'https://dogssite.com', txt: 'Brown Dog' }
, { img: '/data/cat.jpg', link: 'https://catssite.com', txt: 'Black Cat' }
]
const myObj = document.querySelector('#my-div')
arrData.forEach(({ img, link, txt }) =>
{
myObj.innerHTML += `
<p>
<img src="${img}">
<br>
<a target='_blank' href="${link}">${txt}</a>
</p>`
});
<div id="my-div"></div>
This answer is a complete solution. It's exciting to edit the HTML template in codepen and watch the layout of each copy change in real time -- similar to the experience of editing a CSS class and watching the live changes.
Here's the code, followed by explanation.
HTML
<span id="template-container"></span>
<div hidden id="template-data">
IMG,, LINK,, CAPTION
https://www.referenseo.com/wp-content/uploads/2019/03/image-attractive.jpg,, khangssite.com,, Khang Le
https://i.redd.it/jeuusd992wd41.jpg,, suessite.com,, Sue Sneed
https://picsum.photos/536/354,, catssite.com,, Black Cat
</div>
<template id="art-template">
<span class="art-item">
<p>
<a href="${LINK}" target="_blank">
<img src="${IMG}" alt="" />
<br>
${CAPTION}
</a>
</p>
</span>
</template>
Javascript
window.onload = function LoadTemplate() {
// get template data.
let sRawData = document.querySelector("#template-data").innerHTML.trim();
// load header and data into arrays
const headersEnd = sRawData.indexOf("\n");
const headers = sRawData.slice(0, headersEnd).split(",,");
const aRows = sRawData.slice(headersEnd).trim().split("\n");
const data = aRows.map((element) => {
return element.split(",,");
});
// grab template and container
const templateHtml = document.querySelector("template").innerHTML;
const container = document.querySelector("#template-container");
// make html for each record
data.forEach((row) => {
let workingCopy = templateHtml;
// load current record into template
headers.forEach((header, column) => {
let value = row[column].trim();
let placeholder = `\$\{${header.trim()}\}`;
workingCopy = workingCopy.replaceAll(placeholder, value);
});
// append template to page, and loop to next record
container.innerHTML += workingCopy;
});
};
New version on github:
https://github.com/johnaweiss/HTML-Micro-Templating
Requirement
As specified in the question, this solution is intended to optimize the coding experience on the HTML side. That's the whole point of any web templating. Therefore, the JS has to work a little harder to make life easier for the HTML programmer.
The question seeks a reusable solution. Therefore, JS should be ignorant of the template, fields, and data-list. So unlike #MisterJojo's answer, the template and all data are in my HTML, not javascript. The JS code is generic.
Design
My solution is based on the <template> tag, which is intended for precisely this usage. It has various advantages, like the template isn't displayed, processed, or validated by the browser, so it has less impact on performance. Programmer doesn't have to write an explicit display:none style.
https://news.ycombinator.com/item?id=33089975
However, <template> tags are normally only intended for loading content into the layout. That's inadequate. This tool allows template variables anywhere in the HTML, including inside the tags (eg attributes like <img src).
HTML
My HTML has three blocks:
template: The HTML coder develops their desired display-structure of the output, in real HTML (not plain text). Uses <template>
data: The list of records each of which should be rendered using the same template. Uses <span> with a HIDDEN attribute.
container: The place to display all the output blocks. Uses <span>.
Template
My sample template includes 3 placeholders for data:
${LINK}
${IMG}
${CAPTION}
But of course you can use any placeholders, any number of them. I use string-literal delimiting-style (although i'm not actually using them as string-literals -- i just borrowed the delimiter style.)
Data Element
The question specifies data should be stored in HTML. It should require minimal keystrokes.
I didn't want to redundantly retype the fieldnames on every row. I didn't use slotting, JSO, Jason, or XML syntax, because those are all verbose.
https://developer.mozilla.org/en-US/docs/Web/Web_Components/Using_templates_and_slots
It's a simple delimited list. I eliminated all braces, brackets, equals, parens, colons etc.
I put the fieldname-headers only on the first row. The headers are a visual aid for the HTML developer, and a key for Javascript to know the fieldnames and order.
Record Delimiter: End-of-line
Field Delimiter: Double-commas. Seems safe, and they're easy to type. I don't expect to see double-commas in any actual data. Beware, the developer must enter a space for any empty cells, to prevent unintended double-commas. The programmer can easily use a different delimiter if they prefer, as long as they update the Javascript. You can use single-commas if you're sure there will be no embedded commas within a cell.
The data block is hidden using the hidden attribute. No CSS needed.
It's a span to ensure it takes up no room on the page.
JAVASCRIPT
Data
The data is processed by Javascript with two split statements, first on newline delimiter, then on the double-comma delimiter. That puts the whole thing into a 2D array. My JS uses trims to get rid of extra whitespace as needed.
Place-holder Substitution
Handling multiple entries requires plugging each entry into the template.
i went with simple string-replacement instead of string literals.
Multiple Templates
New version which supports multiple templates, and ability to use same template in multiple locations on same page.
https://github.com/johnaweiss/HTML-Micro-Templating
Future
Inspired by #MisterJojo, an earlier version of my solution used template literals to do the substitution. However, that was a bit more complicated and verbose, and seemed to require use of eval. So i switched to .replaceAll. Yet template-literals seems like a more appropriate method for templates, so maybe i'll revisit that.
A future version may adapt to whatever custom field-delimiter the HTML developer uses for the data block.
The dollar-curly delimiter for placeholders is a bit awkward to type. So i'm interested in finding a less awkward non-alpha delimiter that won't conflict with HTML. Considering double-brackets or braces [[NAME]]
Maybe there are simpler ways to pull the data-table into JS.
I've read components work well with <template>, but i didn't go there.
Imo, the JS committee should develop a variable-placeholder feature for <template> tags, and natively accommodate storing the data in HTML. It would be great if something like this solution was part of the rendering engine.
Let's say I have a variable in my typescript class called description and the type is String.
And what I want is that I can pass HTML elements inside the description variable, specifically I want to be able to pass new lines. And that I can add the string tag to a paragraph tag and that is aplies the html inside the string
I tried to put '\n' and also <br> in the description variable but I did not get the result I wanted. All the text was still outputted in one line.
This is the html btw:
Result:
Is it Possible what I want and know. If not what could be better alternatives for this problem.
You can bind to the innerHtml of the element, which should render your <br> tags:
<p [innerHtml]="description"></p>
You can do something like this which all allows you to pass in html in your variable https://medium.com/#swarnakishore/angular-safe-pipe-implementation-to-bypass-domsanitizer-stripping-out-content-c1bf0f1cc36b
I have a paragraph that is enclosed in artist.bio.summary. This variable contains all the details about an artist. This is fetched from somewhere else. I am printing this out inside a p tag.
My problem is there is a link inside this p tag within a a tag.
The a tag is like this;
Read more
The p tag just prints this out rather than giving me a link to click.
What should I do to act accordingly?
I am calling this property as below:
<p>{artist.bio.summary}</p>
let artist = {
bio: { summary: '' }
};
I had set this artist.bio.summary as a string initially.
And an example string that i am getting is below:
"hello Read more there"
The above string is the content of the artist.bio.summary once i received it
This is a security issue and is not allowed by React (by default) so it's as expected to not evaluate the embedded html markup, but they have a workaround if you really want to. dangerouslySetInnerHTML
<p dangerouslySetInnerHTML={artist.bio.summary}></p>
But please read up on injection attacks so you understand the consequences before using this kind of dynamic evals.
https://www.codeproject.com/Articles/134024/HTML-and-JavaScript-Injection
From you description it seems that artist.bio.summary contains the entire content i.e Read more . In that case what you need is dangerouslySetInnerHTML
<p dangerouslySetInnerHTML={{__html: artist.bio.summary}}/>
However I would suggest you to make modifications to your data such that you aren't actually passing the HTML to the React component but creating it using JSX yourself
I am making a forum with markdown support.
I've been using meteor's markdown parser {{#markdown}} and have found something disturbing that I can't seem to figure out.
I am using {{#markdown}}{{content}}{{/markdown}} to render the content inserted into database.
The disturbing thing, for example, if someone writes up html without inserting it into the code block in the content...
example
<div class = "col-md-12">
Content Here
</div>
This will render as a column. They could also make buttons and etc through writing the HTML for it.
How to disable this behaviour so that when HTML is written it will not render into HTML but just simply show it as text?
You can write global helper, which will strip all html tags:
function stripHTML(string){
s = string.replace(/(<([^>]+)>)/ig, '');
return s;
}
Template.registerHelper('stripHTML', stripHTML)
Usage :
{{#markdown}}{{stripHTML content}}{{/markdown}}
Test it in console:
stripHTML("<div>Inside dive</div> Text outside")
I need help understanding behavior of render_string in tornado.
I am using below code.
tornado.escape.to_basestring(self.render_string("message.html", input_to_template=message))
message.html
<div class="message">{% module linkify(input_to_template["body"]) %}</div>
if message["html"] is data then the output of to_basestring is
<div class="message">data</div>\n
Now, if message["html"] is <img src="/media//uploads/Capture_23.PNG" />
<div class="message"><img src="/media//uploads/Capture_23.PNG" /></div>\n
From the documentation , this function render_string,
"""
Generate the given template with the given arguments.
We return the generated byte string (in utf8). To generate and
write a template as a response, use render() above.
"""
It does not mention anything about escaping/unescaping html tags .
How can I use this function , so that if message["html"] is <img src="/media//uploads/Capture_23.PNG" /> ,
I get output as
<div class="message"><img src="/media//uploads/Capture_23.PNG" /></div>\n
The tornado template system automatically escapes everything except the output of modules or the raw directive; modules are expected to do their own escaping. In this case the escaping is actually done by the linkify module.
linkify takes plain text and turns it into html, so it must assume that any angle brackets are meant to be shown verbatim, and escapes them. You don't want to actually pass <img> tags through linkify because it's not smart enough to see the src attribute, and if you had an absolute url it would become <img src="url">.
If you want to include message["html"] with no escaping, the simplest way is to use the raw directive: {% raw message["html"] %}. See the template docs at http://www.tornadoweb.org/en/stable/template.html