Parse an HTML string with JS

Parse an HTML string with JS

I searched for a solution but nothing was relevant, so here is my problem:
I want to parse a string which contains HTML text. I want to do it in JavaScript.
I tried this library but it seems that it parses the HTML of my current page, not from a string. Because when I try the code below, it changes the title of my page:
var parser = new HTMLtoDOM(“titleTesttest01test02test03“, document);

My goal is to extract links from an HTML external page that I read just like a string.
Do you know an API to do it?

Solutions/Answers:

Solution 1:

Create a dummy DOM element and add the string to it. Then, you can manipulate it like any DOM element.

var el = document.createElement( 'html' );
el.innerHTML = "<html><head><title>titleTest</title></head><body><a href='test0'>test01</a><a href='test1'>test02</a><a href='test2'>test03</a></body></html>";

el.getElementsByTagName( 'a' ); // Live NodeList of your anchor elements

Edit: adding a jQuery answer to please the fans!

var el = $( '<div></div>' );
el.html("<html><head><title>titleTest</title></head><body><a href='test0'>test01</a><a href='test1'>test02</a><a href='test2'>test03</a></body></html>");

$('a', el) // All the anchor elements

Solution 2:

It’s quite simple:

var parser = new DOMParser();
var htmlDoc = parser.parseFromString(txt, 'text/html');
// do whatever you want with htmlDoc.getElementsByTagName('a');

According to MDN, to do this in chrome you need to parse as XML like so:

var parser = new DOMParser();
var htmlDoc = parser.parseFromString(txt, 'text/xml');
// do whatever you want with htmlDoc.getElementsByTagName('a');

It is currently unsupported by webkit and you’d have to follow Florian’s answer, and it is unknown to work in most cases on mobile browsers.

Edit: Now widely supported

Solution 3:

EDIT: The solution below is only for HTML “fragments” since html,head and body are removed. I guess the solution for this question is DOMParser’s parseFromString() method.


For HTML fragments, the solutions listed here works for most HTML, however for certain cases it won’t work.

For example try parsing <td>Test</td>. This one won’t work on the div.innerHTML solution nor DOMParser.prototype.parseFromString nor range.createContextualFragment solution. The td tag goes missing and only the text remains.

Only jQuery handles that case well.

So the future solution (MS Edge 13+) is to use template tag:

function parseHTML(html) {
    var t = document.createElement('template');
    t.innerHTML = html;
    return t.content.cloneNode(true);
}

var documentFragment = parseHTML('<td>Test</td>');

For older browsers I have extracted jQuery’s parseHTML() method into an independent gist – https://gist.github.com/Munawwar/6e6362dbdf77c7865a99

Solution 4:

var $doc = new DOMParser().parseFromString($html, "text/html");
$As = $('a', $doc);

Solution 5:

The following function parseHTML will return either :


The code :

function parseHTML(markup) {
    if (markup.toLowerCase().trim().indexOf('<!doctype') === 0) {
        var doc = document.implementation.createHTMLDocument("");
        doc.documentElement.innerHTML = markup;
        return doc;
    } else if ('content' in document.createElement('template')) {
       // Template tag exists!
       var el = document.createElement('template');
       el.innerHTML = markup;
       return el.content;
    } else {
       // Template tag doesn't exist!
       var docfrag = document.createDocumentFragment();
       var el = document.createElement('body');
       el.innerHTML = markup;
       for (i = 0; 0 < el.childNodes.length;) {
           docfrag.appendChild(el.childNodes[i]);
       }
       return docfrag;
    }
}

How to use :

var links = parseHTML('<!doctype html><html><head></head><body><a>Link 1</a><a>Link 2</a></body></html>').getElementsByTagName('a');

Solution 6:

The fastest way to parse HTML in Chrome and Firefox is Range#createContextualFragment:

var range = document.createRange();
range.selectNode(document.body); // required in Safari
var fragment = range.createContextualFragment('<h1>html...</h1>');
var firstNode = fragment.firstChild;

I would recommend to create a helper function which uses createContextualFragment if available and falls back to innerHTML otherwise.

Benchmark: http://jsperf.com/domparser-vs-createelement-innerhtml/3