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

Question

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?

Answer 1

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.

Answer 2

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