A simple jQuery function to change a class every 2 seconds.

JavaScript: Change a class every 2 seconds

function switchClass(){
 
    var delay = 2000;
    var colors = new Array ("red", "grey", "green", "blue");
    var i = 0;
  
    setInterval(function(){
        
        $('span').removeClass(colors[i]);
        i++;
        if(i== colors.length) i=0;
        $('span').addClass(colors[i]);
        
    }, delay);
}