If you are talking about the info bar at the bottom of the browser, that is showing what websites are currently sending data to the window.

when i open any website then every time at bottom this website " s.crimethreatalert.com" this message , i think due to that browser is loading or navigate to slow, please giv me solution.

I did some research. S.crimethreatalert.com is a malicious website

Further information can be found in the Troubleshoot Firefox issues caused by malware article.

Run most or all of the listed malware scanners. Each works differently. If one program misses something, another may pick it up.