In Safari, how to switch tabs using mouse gesture? I try to use the BetterTouchTool, since there's no shortcut to switch tabs, I have no idea how to config in BetterTouchTool too.
Since you have BetterTouchTool, this is pretty easy. Simply choose whatever gestures you want to use for tab-switching and assign them the following keyboard shortcuts:
These shortcuts are CtrlTab and CtrlShiftTab respectively. The first shortcut will switch to the next tab, and the latter will switch to the previous tab.