govspiders govspiders - 10 days ago 6
Javascript Question

Using Greasemonkey to hide a multilevel parent of select nodes?

What I'm looking to do COULD be accomplished easily if CSS4 standards were in-place. But, I am looking to do something similar with Greasemonkey in the meantime and learn more about parent selectors.

My early attempt looks a little like this:

$(document).find("minds-remind").parentElement.style.display = 'none';


The element I'm looking to access is:

minds-activity < div < div < minds-remind


So if it contains
minds-remind
, then hide parent
minds-activity
only in that instance. There are hundreds of minds-activity elements, I only want those containing
div div minds-remind
to become hidden.

Any help would be much appreciated and I am anxious to better understand how to go about pursuing this in the future. :)

Answer

You seem to be trying to use jQuery, so you can use the jQuery :has selector. Like so:

$(".minds-activity:has('.minds-remind')").hide ();


Or more precise (but also more brittle):

$(".minds-activity > div > div > .minds-remind").parents (".minds-activity").hide ();


The plain javascript equivalent:

document.querySelectorAll (".minds-activity > div > div > .minds-remind").forEach ( function (node) {
    node.parentNode.parentNode.parentNode.style.display = "none";
} );

For AJAX driven pages, use waitForKeyElements(), like so:

// ==UserScript==
// @name     _Hiding ancestors of select content
// @match    http://YOUR_SERVER.COM/YOUR_PATH/*
// @require  http://ajax.googleapis.com/ajax/libs/jquery/2.1.0/jquery.min.js
// @require  https://gist.github.com/raw/2625891/waitForKeyElements.js
// @grant    GM_addStyle
// ==/UserScript==
//- The @grant directive is needed to restore the proper sandbox.

waitForKeyElements (
    ".minds-activity > div > div > .minds-remind", hideAncestor
);

function hideAncestor (jNode) {
    jNode.parents (".minds-activity").hide ();
}


Comparing the "┬┐good enough?" selector to the more precise/brittle one (Run the code snippet button, below):

$("button").click ( function (zEvent) {
    $("body > div").removeAttr ("style");
    switch (zEvent.target.id) {
        case "okay":
            $(".minds-activity:has('.minds-remind')").css ("background", "pink");
            break;
        case "precise":
            $(".minds-activity > div > div > .minds-remind").parents (".minds-activity").css ("background", "pink");
            break;
        default:
            console.error ("Missing case in button click handler: ", zEvent.target.id);
            break;
    }
} );
body > div {
    margin: 1ex;
    border: 1px solid gray;
    border-radius: 1ex;
    display: inline-block;
}
body > div > div {
    display: table;
    height: 3em;
}
body > div > div > div {
    display: table-cell;
    vertical-align: middle;
    min-width: 20vw;
    text-align: center;
}
button { margin: 1ex; }
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.0/jquery.min.js"></script>
<div class="minds-activity">
    <div><div><div class="">Good</div></div></div>
</div>
<div class="minds-activity">
    <div><div><div class="minds-remind">Bad</div></div></div>
</div>
<div class="minds-activity">
    <div><div><div><div class="minds-remind">Ugly</div></div></div></div>
</div>
<div class="hive-minds">
    <div><div><div class="minds-remind">Martian</div></div></div>
</div>
<button id="okay">Test good enough jQuery</button>
<button id="precise">Test precise jQuery</button>

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