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.
I have a sort of strange use-case in Angular 2 where I have some content that contains regular html tags as well as custom html tags. I want to render the regular html tags and show the custom html tags as plain text. For example
the <CUSTOM_TAG>boy</CUSTOM_TAG> went to the <b>store</b>
should have <CUSTOM_TAG>boy</CUSTOM_TAG> appearing as plain text just as you see it above, however <b>store</b> should appear as store i.e. the bold tag is actually rendered.
When I try the usual way of inserting html i.e.
<div [innerHtml]="myHtml"></div>
I get a sanitization error because of the custom tag. When I fix the sanitization error as was done here it just strips out the custom tags which I also don't want. Is showing the custom tags as plain text and rendering the regular html tags possible?
If all the possible custom tags are known, you can encode them before passing the string to the [innerHTML] binding. The method encodeCustomTags in the following code snippet uses a regular expression to replace <customTag> with <customTag>:
private customTags = [
"CUSTOM_TAG",
"otherTag",
];
myHtml = this.encodeCustomTags("the <CUSTOM_TAG>boy</CUSTOM_TAG> went to the <b>store</b>");
private encodeCustomTags(html: string): string {
let regex: RegExp;
for (let tag of this.customTags) {
regex = new RegExp(`<(/?)${tag}>`, "gi");
html = html.replace(regex, `<$1${tag}>`)
}
return html;
}
See this stackblitz for a demo.
I have a string, read from a database, that contains HTML that I want to output. Despite applying HttpUtility.HtmlDecode(), the View always renders the string as encoded HTML (i.e. <SPAN> instead of <SPAN>).
I am using:
string test = WebUtility.HtmlDecode(myStr);
<span>#test</span>
I have tried:
string test = HttpUtility.HtmlDecode(myStr);
<span>#test</span>
<span>#HttpUtility.HtmlDecode(myStr)</span>
Use Html.Raw()
#Html.Raw("<span>Hello</span>")
All the output from helpers and other elements in Razor are put through HttpUtility.HtmlEncode, unless they implement IHtmlString. But your best option here is using Html.Raw()
You need to use #Html.Raw:
#Html.Raw("<h1>Header</h1>")
Will output the text Header.
Try this helper method
#Html.Raw(myStr)
How can I display marked up string data in a Meteor template?
I need to display a string from my database that contains some basic HTML tags such that the resulting text is properly formatted. It currently just displays the markup text.
Here's the relevant part of the template:
<span class="description">{{description}}</span>
Where {{description}} is the string containing markup (like "hello<br>world").
I'd like it to display
hello
world
rather than
hello<br>world
I guess this would be similar to using innerHTML in javascript.
Thanks in advance!
To override HTML-escape in Handlebars, use the triple-stash:
<span class="description">{{{description}}}</span>
I don't know if I'm trying to do something against the very nature of SafeHtmlBuilder. The thing is that I'd like to put html code (for instance, an < a > tag) in a div and make it safe. So here is my code:
SafeHtmlBuilder builder = new SafeHtmlBuilder();
builder.append(TEMPLATES.diagramHeader(
BasicConstants.diagramHeaderId + "description",
newBox.getDescription());
newDiv.setInnerHTML(builder.toSafeHtml().asString());
And my template:
#Template("<div id=\"{0}\">{1}</div>") /* Description */
SafeHtml diagramHeader(String idDesc, String description);
When getDescription() returns a string with html code (e.g., an < a > tag) and the contents of newDiv are rendered, I don't see the hyperlink, what I see is the HTML CODE of the hyperlink.
I would like to see the hyperlink, how can I do this? (I am willing to sacrifice HTML's safety for the cause).
Thanks!
If the description argument to the template can contain markup, then it should be of type SafeHtml.
You'd then use SafeHtmlUtils.fromTrustedString(newBox.getDescription()), as you're trusting newBox.getDescription() to be safe.
As a side note, I don't understand why:
you use a SafeHtmlBuilder to append() only once
you use setInnerHTML instead of setInnerSafeHtml (maybe you're not using GWT 2.5?)