How to implement “prevUntil” in Vanilla JavaScript without libraries?

Question

I need to implement the functionality of jQuery\'s prevUntil() method in Vanilla JavaScript.

I\'ve got several

elements on the same level:

Answer 1

How about this:

while ( node = node.previousElementSibling ) {
    if ( ( ' ' + node.className + ' ' ).indexOf( 'foo' ) !== -1 ) {
        // found; do your thing
        break;
    }
}

Don't bother telling me that this doesn't work in IE8...