Getting a jQuery selector for an element

Squeegy_62076 0
Viewed 38373

In psuedo code, this is what I want.

var selector = $(this).cssSelectorAsString(); // Made up method...
// selector is now something like: "html>body>ul>li>img[3]"
var element = $(selector);

The reason is that I need to pass this off to an external environment, where a string is my only way to exchange data. This external environment then needs to send back a result, along with what element to update. So I need to be able to serialize a unique CSS selector for every element on the page.

I noticed jquery has a selector method, but it does not appear to work in this context. It only works if the object was created with a selector. It does not work if the object was created with an HTML node object.

jquery-selectors jquery javascript
10 Answers

I see now that a plugin existed (with the same name I thought of too), but here's just some quick JavaScript I wrote. It takes no consideration to the ids or classes of elements – only the structure (and adds :eq(x) where a node name is ambiguous).

jQuery.fn.getPath = function () {
    if (this.length != 1) throw 'Requires one element.';

    var path, node = this;
    while (node.length) {
        var realNode = node[0], name = realNode.name;
        if (!name) break;
        name = name.toLowerCase();

        var parent = node.parent();

        var siblings = parent.children(name);
        if (siblings.length > 1) { 
            name += ':eq(' + siblings.index(realNode) + ')';
        }

        path = name + (path ? '>' + path : '');
        node = parent;
    }

    return path;
};

(License: MIT)

user_1190810

jQuery-GetPath is a good starting point: it'll give you the item's ancestors, like this:

var path = $('#foo').getPath();
// e.g., "html > body > div#bar > ul#abc.def.ghi > li#foo"
user_1076130

Update: This code was changed since then. You may find the implementation of the function now at css-login.js

Original answer: You may also have a look at findCssSelector, which is used in Firefox developer tools to save the currently selected node upon page refreshes. It doesn't use jQuery or any library.

const findCssSelector = function(ele) {
ele = getRootBindingParent(ele);
  let document = ele.ownerDocument;
  if (!document || !document.contains(ele)) {
    throw new Error("findCssSelector received element not inside document");
  }

  let cssEscape = ele.ownerGlobal.CSS.escape;

  // document.querySelectorAll("#id") returns multiple if elements share an ID
  if (ele.id &&
      document.querySelectorAll("#" + cssEscape(ele.id)).length === 1) {
    return "#" + cssEscape(ele.id);
  }

  // Inherently unique by tag name
  let tagName = ele.localName;
  if (tagName === "html") {
    return "html";
  }
  if (tagName === "head") {
    return "head";
  }
  if (tagName === "body") {
    return "body";
  }

  // We might be able to find a unique class name
  let selector, index, matches;
  if (ele.classList.length > 0) {
    for (let i = 0; i < ele.classList.length; i++) {
      // Is this className unique by itself?
      selector = "." + cssEscape(ele.classList.item(i));
      matches = document.querySelectorAll(selector);
      if (matches.length === 1) {
        return selector;
      }
      // Maybe it's unique with a tag name?
      selector = cssEscape(tagName) + selector;
      matches = document.querySelectorAll(selector);
      if (matches.length === 1) {
        return selector;
      }
      // Maybe it's unique using a tag name and nth-child
      index = positionInNodeList(ele, ele.parentNode.children) + 1;
      selector = selector + ":nth-child(" + index + ")";
      matches = document.querySelectorAll(selector);
      if (matches.length === 1) {
        return selector;
      }
    }
  }

  // Not unique enough yet.  As long as it's not a child of the document,
  // continue recursing up until it is unique enough.
  if (ele.parentNode !== document) {
    index = positionInNodeList(ele, ele.parentNode.children) + 1;
    selector = findCssSelector(ele.parentNode) + " > " +
      cssEscape(tagName) + ":nth-child(" + index + ")";
  }

  return selector;

};
user_959700
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