Localhost ( local web server ) in the device cannot be accessed

I've got a Galaxy Tab 4 TS-531 and want to run KSWEB server for php/mysql works. But as soon as I try to open the page localhost:8080 , some kind of file starts automatically starts downloading . This happens every time I try to open the address ? I've searched a bit and other questions here seem to indicate towards some kind of proxy error . But I don't know how to deal with that . What's the solution ?