Select element by exact match of its content

No, there's no jQuery (or CSS) selector that does that.

You can readily use filter:

$("p").filter(function() {
    return $(this).text() === "hello";
}).css("font-weight", "bold");

It's not a selector, but it does the job. :-)

If you want to handle whitespace before or after the "hello", you might throw a $.trim in there:

return $.trim($(this).text()) === "hello";

For the premature optimizers out there, if you don't care that it doesn't match <p><span>hello</span></p> and similar, you can avoid the calls to $ and text by using innerHTML directly:

return this.innerHTML === "hello";

...but you'd have to have a lot of paragraphs for it to matter, so many that you'd probably have other issues first. :-)

So Amandu's answer mostly works. Using it in the wild, however, I ran into some issues, where things that I would have expected to get found were not getting found. This was because sometimes there is random white space surrounding the element's text. It is my belief that if you're searching for "Hello World", you would still want it to match " Hello World ", or even "Hello World \n". Thus, I just added the "trim()" method to the function, which removes surrounding whitespace, and it started to work better.

Specifically...

$.expr[':'].textEquals = function(el, i, m) {
    var searchText = m[3];
    var match = $(el).text().trim().match("^" + searchText + "$")
    return match && match.length > 0;
}

Also, note, this answer is extremely similar to Select link by text (exact match)

And secondary note... trim only removes whitespace before and after the searched text. It does not remove whitespace in the middle of the words. I believe this is desirable behavior, but you could change that if you wanted.

Try add a extend pseudo function:

$.expr[':'].textEquals = $.expr.createPseudo(function(arg) {
    return function( elem ) {
        return $(elem).text().match("^" + arg + "$");
    };
});

Then you can do:

$('p:textEquals("Hello World")');

You can use jQuery's filter() function to achieve this.

$("p").filter(function() {
// Matches exact string   
return $(this).text() === "Hello World";
}).css("font-weight", "bold");