// basic.js

function swap(which) {
    var i = $(which);
    var s = i.src;
	var p = s.split('_');
    if (p[2]=='off.jpg') i.src = p[0]+'_'+p[1]+'_on.jpg';
    else i.src = p[0]+'_'+p[1]+'_off.jpg';
}