curTime = Array();
 
curTime[0] = (new Date()).getTime();
 
alert('hello');
 
curTime[1] = (new Date()).getTime();
 
alert('world');
 
curTime[2] = (new Date()).getTime();
 
for( i=1; i<curTime.length; i++ ){
    deltaTime = curTime[i] - curTime[i-1];
    console.log( "["+(i-1)+"]-["+i+"] execution time: " + deltaTime + " ms" );
}
 
deltaTime = curTime[curTime.length-1] - curTime[0] ;
 
console.log( "Total execution time: " + deltaTime + " ms" );