>I pass a URL in a hiden field but when I get the value on the server the "\" are not there and also some data is missing.
>
>This is what I passe.
>

>document.InitCommande.FileUrl.value="TPI\EST\02S\dwg\02S00C\02S00C3b\E1.tif"
>

>This is What I get when I read the field.
>

>TPIESTSdwgS00CS00C3bE1.tif
>

>
>Do I need to incode this string?

It is probably taking the \ as control chars,
try replacing them with \\

"TPI\\EST\\02S\\dwg\\02S00C\\02S00C3b\\E1.tif"

in C#, i have seen people doing

@"TPI\EST\02S\dwg\02S00C\02S00C3b\E1.tif"

which apparently says ignore controls chars, but thats only for C# :)