Can not drag the blocks in mobile browser

I am using mobile web browser to create canvas paint app but the get blocks for the flung ,dragged is not visible when I am trying them to get

Welcome Piya.

App Inventor is not designed to be used to develop apps using a cell phone or tablet although some 'developers' try to do that.

This discussion might help you understand the problem using a mobile browser
Can you write code with android tablet to develop apps using your cell.