jQuery.checkVersion

jQuery.checkVersion.js

jQuery.checkVersion = function( min, max ) {
	var current = jQuery.fn.jquery + 'zz';
	max = ( max || min ) + 'zz';
	min += '0.0.0zz'.substr( min.length );
	return min <= current && current <= max;
};

// This one will also handle 'pre' suffix as minor of 'alpha' and 'beta'.
jQuery.checkVersion = (function(){

	function norm( v, norm_length ) {
		if ( norm_length ) {
			v += '0.0.0'.substr( v.length );
		}
		return v.replace(/p(re)?/, 'AA') + 'zz';
	}
	
	var current = norm( jQuery.fn.jquery );
	
	return function( min, max ) {
		return norm( min, true ) <= current && current <= norm( max || min );
	};

})();

// However, pre/alpha/beta versions would be used only for testing. Ignore them!
jQuery.checkVersion = function( min, max ) {
	return min <= jQuery.fn.jquery && jQuery.fn.jquery <= ( max || min ) + 'z';
};

Will this approach fail when testing that 1.4.9 is between 1.4.1 and 1.4.10?

Either way, check out my take: http://gist.github.com/460275

Will this approach fail when testing that 1.4.9 is between 1.4.1 and 1.4.10?

Yes, it will, but I don't think it is an issue since 1.4.10 is not a valid jQuery version - or you are more informed then me.

Right now, there aren't any jQuery versions where a "part" is double-digits, so it doesn't matter. I was just thinking in terms of future-prrofing.