User:Omegatron/monobook.js/replacetab.js

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function replace() {
    var s = prompt("Search regexp?");
    if(s) {
        var r = prompt("Replace regexp?");
        if(!r && r != '') return;
        var txt = document.editform.wpTextbox1;
        txt.value = txt.value.replace(new RegExp(s, "g"), r);
    }
}

$(function () {
    if(document.forms.editform) {
        mw.util.addPortletLink('p-cactions', 'javascript:replace()', 'replace', 'ca-replace', 'Regexp replace for the edit window', '', 'ca-history');
    }
});