highlight word

highlight.js

function highlightWord(root, word, className) {
    // base on https://stackoverflow.com/a/10730063
    // word is lower-case
    var walker, textNodes = [];

    walker = document.createTreeWalker(root, NodeFilter.SHOW_TEXT, {
        acceptNode: function (node) {
            if (node.nodeType === Node.TEXT_NODE && node.textContent.toLowerCase().indexOf(word) >= 0) {
                return NodeFilter.FILTER_ACCEPT;
            } else {
                return NodeFilter.FILTER_SKIP;
            }
        }
    }, false);

    while (walker.nextNode()) {
        textNodes.push(walker.currentNode);
    }

    textNodes.forEach(function (node) {
        var index, length, span, current, next;
        length = word.length;
        current = node;
        while ((index = current.nodeValue.toLowerCase().indexOf(word)) > -1) {
            next = current.splitText(index + length);
            span = document.createElement("span");
            span.className = className;
            span.appendChild(current.splitText(index));
            next.parentNode.insertBefore(span, next);
            current = next;
        }
    });
}