var h=60;

day=new Date()     //..get the date
x=day.getHours()    //..get the hour
y=day.getMinutes() //.. get he minutes

z= (x * h) + y

dawn=dawn.split(":")
dh=dawn[0];
dm=dawn[1];
dh=(dh * h)
dawn=parseInt(dh) + parseInt(dm)

dusk=dusk.split(":")
dh=dusk[0];
dm=dusk[1];
dh=(dh * h)
dusk=parseInt(dh) + parseInt(dm)

if(z>dawn && z<dusk){
document.write('<style type="text/css">.tgt{background-image:url(back2.jpg);}"</style>')
} else {
document.write('<style type="text/css">.tgt{background-image:url(pageNight.jpg);}"</style>')
}