Note: After saving, you have to bypass your browser's cache to see the changes. Internet Explorer: press Ctrl-F5, Mozilla: hold down Shift while clicking Reload (or press Ctrl-Shift-R), Opera/Konqueror: press F5, Safari: hold down Shift + Alt while clicking Reload, Chrome: hold down Shift while clicking Reload.
// ReplacerfunctionwpTextboxReplace(){vars=prompt("Search regexp:");if(s){varr=prompt("Replace /"+s+"/ with:");if(!r&&r!=='')return;vartxt=document.editform.wpTextbox1;txt.value=txt.value.replace(newRegExp(s,"mg"),r);}}$(function(){if(document.forms.editform){mw.util.addPortletLink('p-cactions','javascript:wpTextboxReplace()','Replace','ca-replace','Regexp replace for the edit window','R',document.getElementById('ca-history'));}});