Can't get jquery animate to work

Can't get jquery animate to work

I have a validation and depending on if its correct or wrong i want it to
animate the textboxes background-color in different colors: Red if its
wrong and green if its correct input. I have tried all different
combinations but i just cant get it to work.
$("#PersonId").animate({background: "#ff2cf0"});
$( "#PersonId" ).animate({
backgroundColor: "#aa0000",
}, 1000 );
etc etc.. What am i doing wrong? I have implemented the JQuery UI file to
my .NET project so i don't think it is anything wrong there.