ZALGO Bookmarklet

javascript:(function(){var a=document.activeElement;if("selectionStart" in a){var b=a.selectionStart,c=a.selectionEnd,d=a.value;a.value=d.substr(0,b)+d.substr(b,c).split("").map(function(a){for(var b=Math.ceil(12*Math.random()),c=0;b>c;c++)a+=String.fromCharCode(768+Math.floor(111*Math.random()));return a}).join("")+d.substr(c)}})()