I'm writing a chrome extension which does the following:

1. Downloads a file from a website to memory using XMLHttpRequest


2. Adds additional data to the file and then base64 encodes the result to the variable total_encoded_data


3. Offers the data to the user using <a href=data:application/octet-stream;charset=utf-8;base64,' + total_encoded_data+' download='file.bin'>Click to Download</a>. Where total_encoded_data is added to href using jQuery.

I have found, through a manual binary search, that if the size of total_encoded_data is greater than 2097100 characters, then I will get an Aw, Snap message when I click the link. If the size is smaller, then I can download as expected.

In addition to testing the filesize, I also used atoi to ensure that the base64 encoding is valid, and it operates without error.

The Aw, Snap messages don't produce any crash reports in chrome://crashes nor any unexpected output in the chrome_debug.log

How do I avoid an Aw, Snap message when serving a data uri where the base64 encoded string length is greater than 2097100?