Is there a way to validate a Sizzle selector?

Question

Is there a way to validate (verify that its constructed correctly) a Sizzle selector without running it?

Answer 1

Well, as Russ says, since Sizzle interprets the selector, it cannot validate it without evaluating it.

However, you can catch the exception thrown by Sizzle to determine if a selector is valid or not:

function isSelectorValid(selector)
{
    try {
        $(selector);
    } catch (x) {
        return false;
    }
    return true;
}

Your can test this solution here.

---

EDIT: For the sake of history, my original (and overengineered) answer was:

However, it's possible to temporarily override Sizzle's error management in order to extract a boolean value from the error status of its last parse operation. The following solution takes advantage of the fact that jQuery exposes Sizzle through $.find (so far):

function isSelectorValid(selector)
{
    var oldErrorMethod = $.find.error;
    try {
        $.find.error = function(msg) {
            valid = false;
            oldErrorMethod(msg);
        };
        $(selector);
        return true;
    } catch (x) {
        return false;
    } finally {
        $.find.error = oldErrorMethod;
    }
}

That can arguably be considered as a horrible hack, but it works: you can test it here.