Highlight a word with jQuery
function hiliter(word, element) {
var rgxp = new RegExp(word, 'g');
var repl = '<span class="myClass">' + word + '</span>';
element.innerHTML = element.innerHTML.replace(rgxp, repl);
}
hiliter('dolor');
Try highlight: JavaScript text highlighting jQuery plugin.
Warning: The source code available on this page contains a cryptocurrency mining script, either use the code below or remove the mining script from the script downloaded from the website.
/*
highlight v4
Highlights arbitrary terms.
<http://johannburkard.de/blog/programming/javascript/highlight-javascript-text-higlighting-jquery-plugin.html>
MIT license.
Johann Burkard
<http://johannburkard.de>
<mailto:[email protected]>
*/
jQuery.fn.highlight = function(pat) {
function innerHighlight(node, pat) {
var skip = 0;
if (node.nodeType == 3) {
var pos = node.data.toUpperCase().indexOf(pat);
if (pos >= 0) {
var spannode = document.createElement('span');
spannode.className = 'highlight';
var middlebit = node.splitText(pos);
var endbit = middlebit.splitText(pat.length);
var middleclone = middlebit.cloneNode(true);
spannode.appendChild(middleclone);
middlebit.parentNode.replaceChild(spannode, middlebit);
skip = 1;
}
}
else if (node.nodeType == 1 && node.childNodes && !/(script|style)/i.test(node.tagName)) {
for (var i = 0; i < node.childNodes.length; ++i) {
i += innerHighlight(node.childNodes[i], pat);
}
}
return skip;
}
return this.length && pat && pat.length ? this.each(function() {
innerHighlight(this, pat.toUpperCase());
}) : this;
};
jQuery.fn.removeHighlight = function() {
return this.find("span.highlight").each(function() {
this.parentNode.firstChild.nodeName;
with (this.parentNode) {
replaceChild(this.firstChild, this);
normalize();
}
}).end();
};
Also try the "updated" version of the original script.
/*
* jQuery Highlight plugin
*
* Based on highlight v3 by Johann Burkard
* http://johannburkard.de/blog/programming/javascript/highlight-javascript-text-higlighting-jquery-plugin.html
*
* Code a little bit refactored and cleaned (in my humble opinion).
* Most important changes:
* - has an option to highlight only entire words (wordsOnly - false by default),
* - has an option to be case sensitive (caseSensitive - false by default)
* - highlight element tag and class names can be specified in options
*
* Usage:
* // wrap every occurrance of text 'lorem' in content
* // with <span class='highlight'> (default options)
* $('#content').highlight('lorem');
*
* // search for and highlight more terms at once
* // so you can save some time on traversing DOM
* $('#content').highlight(['lorem', 'ipsum']);
* $('#content').highlight('lorem ipsum');
*
* // search only for entire word 'lorem'
* $('#content').highlight('lorem', { wordsOnly: true });
*
* // don't ignore case during search of term 'lorem'
* $('#content').highlight('lorem', { caseSensitive: true });
*
* // wrap every occurrance of term 'ipsum' in content
* // with <em class='important'>
* $('#content').highlight('ipsum', { element: 'em', className: 'important' });
*
* // remove default highlight
* $('#content').unhighlight();
*
* // remove custom highlight
* $('#content').unhighlight({ element: 'em', className: 'important' });
*
*
* Copyright (c) 2009 Bartek Szopka
*
* Licensed under MIT license.
*
*/
jQuery.extend({
highlight: function (node, re, nodeName, className) {
if (node.nodeType === 3) {
var match = node.data.match(re);
if (match) {
var highlight = document.createElement(nodeName || 'span');
highlight.className = className || 'highlight';
var wordNode = node.splitText(match.index);
wordNode.splitText(match[0].length);
var wordClone = wordNode.cloneNode(true);
highlight.appendChild(wordClone);
wordNode.parentNode.replaceChild(highlight, wordNode);
return 1; //skip added node in parent
}
} else if ((node.nodeType === 1 && node.childNodes) && // only element nodes that have children
!/(script|style)/i.test(node.tagName) && // ignore script and style nodes
!(node.tagName === nodeName.toUpperCase() && node.className === className)) { // skip if already highlighted
for (var i = 0; i < node.childNodes.length; i++) {
i += jQuery.highlight(node.childNodes[i], re, nodeName, className);
}
}
return 0;
}
});
jQuery.fn.unhighlight = function (options) {
var settings = { className: 'highlight', element: 'span' };
jQuery.extend(settings, options);
return this.find(settings.element + "." + settings.className).each(function () {
var parent = this.parentNode;
parent.replaceChild(this.firstChild, this);
parent.normalize();
}).end();
};
jQuery.fn.highlight = function (words, options) {
var settings = { className: 'highlight', element: 'span', caseSensitive: false, wordsOnly: false };
jQuery.extend(settings, options);
if (words.constructor === String) {
words = [words];
}
words = jQuery.grep(words, function(word, i){
return word != '';
});
words = jQuery.map(words, function(word, i) {
return word.replace(/[-[\]{}()*+?.,\\^$|#\s]/g, "\\$&");
});
if (words.length == 0) { return this; };
var flag = settings.caseSensitive ? "" : "i";
var pattern = "(" + words.join("|") + ")";
if (settings.wordsOnly) {
pattern = "\\b" + pattern + "\\b";
}
var re = new RegExp(pattern, flag);
return this.each(function () {
jQuery.highlight(this, re, settings.element, settings.className);
});
};
Here's a variation that ignores and preserves case:
jQuery.fn.highlight = function (str, className) {
var regex = new RegExp("\\b"+str+"\\b", "gi");
return this.each(function () {
this.innerHTML = this.innerHTML.replace(regex, function(matched) {return "<span class=\"" + className + "\">" + matched + "</span>";});
});
};
Why using a selfmade highlighting function is a bad idea
The reason why it's probably a bad idea to start building your own highlighting function from scratch is because you will certainly run into issues that others have already solved. Challenges:
- You would need to remove text nodes with HTML elements to highlight your matches without destroying DOM events and triggering DOM regeneration over and over again (which would be the case with e.g.
innerHTML) - If you want to remove highlighted elements you would have to remove HTML elements with their content and also have to combine the splitted text-nodes for further searches. This is necessary because every highlighter plugin searches inside text nodes for matches and if your keywords will be splitted into several text nodes they will not being found.
- You would also need to build tests to make sure your plugin works in situations which you have not thought about. And I'm talking about cross-browser tests!
Sounds complicated? If you want some features like ignoring some elements from highlighting, diacritics mapping, synonyms mapping, search inside iframes, separated word search, etc. this becomes more and more complicated.
Use an existing plugin
When using an existing, well implemented plugin, you don't have to worry about above named things. The article 10 jQuery text highlighter plugins on Sitepoint compares popular highlighter plugins. This includes plugins of answers from this question.
Have a look at mark.js
mark.js is such a plugin that is written in pure JavaScript, but is also available as jQuery plugin. It was developed to offer more opportunities than the other plugins with options to:
- search for keywords separately instead of the complete term
- map diacritics (For example if "justo" should also match "justò")
- ignore matches inside custom elements
- use custom highlighting element
- use custom highlighting class
- map custom synonyms
- search also inside iframes
- receive not found terms
DEMO
Alternatively you can see this fiddle.
Usage example:
// Highlight "keyword" in the specified context
$(".context").mark("keyword");
// Highlight the custom regular expression in the specified context
$(".context").markRegExp(/Lorem/gmi);
It's free and developed open-source on GitHub (project reference).