How to by default activate a field/textbox at open page

For my app I want to activate a textbox when the user opens the page, because then the user is directly able to type instead of having to select the box. Of course the user should be able to move away from the tekstbox when the user selects another field. Could someone help me how to do this?
1 answers

You can achieve the desired functionality using the tabindex of the different input widgets.

It basically is a counter which keeps track of what field gets focus next