CODEWITHSUNDEEP
javascriptdomcss-selectors
rcphq
rcphq

Reputation: 1905

Get element's CSS selector (when it doesn't have an id)

I'm trying to modify a page through JavaScript/CSS (much like Stylish or Greasemonkey do). This is a very complex page (that I didn't build, or can't modify pre-render), which makes constructing the CSS selector hard to do (manually looking at document structure). How can I achieve this?

Upvotes: 37

Views: 47885

Answers (6)

Yassine
Yassine

Reputation: 41

function getCssSelector(el)
{
    names = [];
    do {
        index = 0;
        var cursorElement = el;
        while (cursorElement !== null)
        {
            ++index;
            cursorElement = cursorElement.previousElementSibling;
        };
        names.unshift(el.tagName + ":nth-child(" + index + ")");
        el = el.parentElement;
    } while (el !== null);

    return names.join(" > ");
}

Upvotes: 4

Anton Medvedev
Anton Medvedev

Reputation: 3668

Check this CSS selector generator library @medv/finder

  • Generates shortest selectors
  • Unique selectors per page
  • Stable and robust selectors
  • 2.9 kB gzip and minify size

Example of generated selector:

.blog > article:nth-child(3) .add-comment

Upvotes: 6

tutuDajuju
tutuDajuju

Reputation: 10850

I found I could actually use this code from chrome devtools source to solve this, without that many modifications.

After adding relevant methods from WebInspector.DOMPresentationUtils to new namespace, and fixing some differences, I simply call it like so:

> UTILS.cssPath(node)

For implementation example see css_path.js

Upvotes: 22

andrewk
andrewk

Reputation: 3871

you can use for css first-child pseudo classes if the element is a first child in a div table or body..etc

you can use jquery's nth child() function.

http://api.jquery.com/nth-child-selector/

example from jquery.com

<!DOCTYPE html>
<html>
<head>
  <style>

  div { float:left; }
  span { color:blue; }
  </style>
  <script src="http://code.jquery.com/jquery-1.4.4.js"></script>
</head>
<body>
  <div><ul>
    <li>John</li>
    <li>Karl</li>
    <li>Brandon</li>

  </ul></div>
  <div><ul>
    <li>Sam</li>
  </ul></div>

  <div><ul>
    <li>Glen</li>
    <li>Tane</li>
    <li>Ralph</li>

    <li>David</li>
  </ul></div>
<script>$("ul li:nth-child(2)").append("<span> - 2nd!</span>");</script>

</body>
</html>

my 2 cents if I understood the question correctly.

Upvotes: 0

Phrogz
Phrogz

Reputation: 303215

function fullPath(el){
  var names = [];
  while (el.parentNode){
    if (el.id){
      names.unshift('#'+el.id);
      break;
    }else{
      if (el==el.ownerDocument.documentElement) names.unshift(el.tagName);
      else{
        for (var c=1,e=el;e.previousElementSibling;e=e.previousElementSibling,c++);
        names.unshift(el.tagName+":nth-child("+c+")");
      }
      el=el.parentNode;
    }
  }
  return names.join(" > ");
}

console.log(  fullPath( $('input')[0] ) );
// "#search > DIV:nth-child(1) > INPUT:nth-child(1)"

This seems to be what you are asking for, but you may realize that this is not guaranteed to uniquely identify only one element. (For the above example, all the sibling inputs would be matched as well.)

Edit: Changed code to use nth-child instead of CSS classes to properly disambiguate for a single child.

Upvotes: 69

Sean Patrick Floyd
Sean Patrick Floyd

Reputation: 298878

Use FireFox with FireBug installed.

  • Right-click any element
  • Select "Inspect Element"
  • Right click the element in the HTML tree
  • Select "Copy XPath" or "Copy CSS Path"

Output for the permalink to this answer (XPath):

/html/body/div[4]/div[2]/div[2]/div[2]/div[3]/table/tbody/tr/td[2]/table/tbody/tr/td/div/a

CSS Path:

html body.question-page div.container div#content div#mainbar div#answers div#answer-4588287.answer table tbody tr td table.fw tbody tr td.vt div.post-menu a

But regarding this comment:

my final intent is to create a css selector for the object ...

If that is your intent, there may be an easier way through JavaScript:

var uniquePrefix = 'isThisUniqueEnough_';
var counterIndex = 0;
function addCssToElement(elem, cssText){
    var domId;
    if(elem.id)domId=elem.id;
    else{
        domId = uniquePrefix + (++counterIndex);
        elem.id = domId;
    }
    document.styleSheets[0].insertRule("#"+domId+"{"+cssText+"}");
}

The last line may need to be implemented differently for different browsers. Did not test.

Upvotes: 19

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