why I can't run preview on chrome? It always open on other browsers.
It was Opera. But when I uinstalled Opera, IE takes place.
Is it set to be the default browser?
Sometimes, C2 can't properly detect which browser should be used, so in such cases, using 'Custom' is worth trying.
Choose any executable file on disk to be launched for previewing when the Preview browser is set to Custom. For example, you may want to install a pre-release (beta) browser alongside the stable release, and have the option to also preview in the pre-release browser. Alternatively, Construct 2 sometimes cannot detect the traditional browsers even when they are installed, so you can manually specify a browser here.