Are you using the Kendo UI framework, then do it like this:
app :
new
kendo.mobile.Application(document.body, {
ios :
true
,
majorVersion : 5,
minorVersion :
"0.0"
,
flatVersion :
"500"
,
skin:
"flat"
})
or you can do it programmatically if you want to make it switchable:
APP.app.skin(
"flat"
);
// APP.app.skin(""); for default