jQuery -允许在移动设备上自动显示键盘

I have a Rails app that has a closed back-end. On certain pages, I want to auto-select a text input so I can use an external bluetooth scanner to scan a barcode without selecting it with a mouse/touchscreen every time. This works perfectly on non-mobile devices. However, on mobile devices (mostly tablets), I want the keyboard to popup (as the scanners are viewed as "keyboards" by the system). I know this is prevented by iOS, because it could be annoying. However, I want to know:I have a Rails app that has a closed back-end.