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Created May 7, 2012 04:21
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A utility function, for Greasemonkey scripts, that detects and handles AJAXed content.
/*--- waitForKeyElements(): A utility function, for Greasemonkey scripts,
that detects and handles AJAXed content.
Usage example:
waitForKeyElements (
, commentCallbackFunction
//--- Page-specific function to do what we want when the node is found.
function commentCallbackFunction (jNode) {
jNode.text ("This comment changed by waitForKeyElements().");
IMPORTANT: This function requires your script to have loaded jQuery.
function waitForKeyElements (
selectorTxt, /* Required: The jQuery selector string that
specifies the desired element(s).
actionFunction, /* Required: The code to run when elements are
found. It is passed a jNode to the matched
bWaitOnce, /* Optional: If false, will continue to scan for
new elements even after the first match is
iframeSelector /* Optional: If set, identifies the iframe to
) {
var targetNodes, btargetsFound;
if (typeof iframeSelector == "undefined")
targetNodes = $(selectorTxt);
targetNodes = $(iframeSelector).contents ()
.find (selectorTxt);
if (targetNodes && targetNodes.length > 0) {
btargetsFound = true;
/*--- Found target node(s). Go through each and act if they
are new.
targetNodes.each ( function () {
var jThis = $(this);
var alreadyFound = ('alreadyFound') || false;
if (!alreadyFound) {
//--- Call the payload function.
var cancelFound = actionFunction (jThis);
if (cancelFound)
btargetsFound = false;
else ('alreadyFound', true);
} );
else {
btargetsFound = false;
//--- Get the timer-control variable for this selector.
var controlObj = waitForKeyElements.controlObj || {};
var controlKey = selectorTxt.replace (/[^\w]/g, "_");
var timeControl = controlObj [controlKey];
//--- Now set or clear the timer as appropriate.
if (btargetsFound && bWaitOnce && timeControl) {
//--- The only condition where we need to clear the timer.
clearInterval (timeControl);
delete controlObj [controlKey]
else {
//--- Set a timer, if needed.
if ( ! timeControl) {
timeControl = setInterval ( function () {
waitForKeyElements ( selectorTxt,
controlObj [controlKey] = timeControl;
waitForKeyElements.controlObj = controlObj;
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gaveitatry2 commented Jan 8, 2024


Could you convert the following code into waitForKeyElements, please? When I use it as is, it only works on some of the span.rightActionButton elements on each page, but not all of them. So I want to see if it will work if I use wFKE, but I don't know the proper format. Hope you don't mind. Thanks.

$(this).css("background-color", "red");
var oldUrl = $(this).attr("onclick");
var newUrl = oldUrl.replace("window.location='", "'");
$(this).attr("onclick", newUrl + ", target='_blank')");

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BrockA commented Jan 8, 2024

@gaveitatry2 ,

That entire code block would be replaced with:

waitForKeyElements ("span.rightActionButton", rewriteSpanLinks);

function rewriteSpanLinks (jNode) {
    jNode.css ("background-color", "red");
    var oldUrl = jNode.attr ("onclick");
    var newUrl = oldUrl.replace ("window.location='", "'");
    jNode.attr ("onclick", newUrl + ", target='_blank')");

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Thank you.

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cow1337killer3 commented Jun 24, 2024

This code is so bad. It should be using a MutationObserver or DOM/script load events instead of running a jQuery selector on the entire document every 300 ms.

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@cow1337killer3 by all means, rewrite it :)

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