Based off of what you're telling me, it sounds like it's too much for the mobile browser to handle all at once. Does the browser crash on upload or during the process of storing the base64 data in preparation to post. I'm trying to understand where the crash occurs. If you know that the transmission of this amount of data is too much, I recommend finding the limitation. How many characters in this string is it willing to accept without crashing. When you discover this limit, chunk the data and send separate posts one after another. I may be wrong but it's worth looking into. (Chunk Loading)