Showing content while loading

So, I have this script that draws these tables based on SQL queries, and because there is so much data, it takes a while for the script to load the web page. Now, while it's running, the browser screen stays white until it's all loaded, however if I stop the browser, what did load shows up. Is there a way to show the content WHILE the script is running and generating it? Or some other way to avoid the white screen? Like maybe some HTML trick or header or something??