Bookmarklet that allows you to highlight (permanently for that visit) text on page.

highlights

javascript: (function() {
	/* STYLES */
	const css = '.highlight { background: yellow; }';
	const head = document.head || document.getElementsByTagName('head')[0];
	const style = document.createElement('style');

	style.type = 'text/css';
	if (style.styleSheet){
		style.styleSheet.cssText = css;
	} else {
		style.appendChild(document.createTextNode(css));
	}

	head.appendChild(style);


	/* HIGHLIGHT FUNCTION */
	function highlight(text) {
		let innerHTML = document.body.innerHTML.toLowerCase();
		const index = innerHTML.indexOf(text.toLowerCase());
		if ( index >= 0 ) { 
			innerHTML = innerHTML.substring(0,index) + "<span class='highlight'>" + innerHTML.substring(index,index+text.length) + "</span>" + innerHTML.substring(index + text.length);
			document.body.innerHTML = innerHTML 
		}
	}


	/* EVENT HANDLER */
	window.onmouseup = function(e) {
		highlight(window.getSelection().toString());
	};
})();