Webkit gradient background-gradient in html5 progress bar?

[fomilgatemp]

In an attempt to color the inside of the progress bar I use the below code:\[code\]progress::-webkit-progress-bar-value { background-color:-webkit-gradient(linear,left bottom ,left top,from(#C6E6E6),to(#D1E4E6)) ;}\[/code\]However the gradients do not work,Only simple colors.