When I opened the web page I downloaded before ,a http:// get became a file:/// get,why?

I downloaded a web page named map.html which was a web app using Google apis.There was a marker on it.

However,when I opened the local one in the browser,the marker disappeared.And I checked the "developer tools" ,just to find out a get request from http:// had turned into file:/// .

So it accounted for the html not working .The marker.png was on the google web server.And apparently it can't be found on my computer.The weird thing was I opend the original web page and found out the marker.png in the "resource" in developer tools with a link to http://.

The question was how to solve this problem.There was no explicit link to file:// in the html indeed .