Regular expression to determine if a string contains a valid regular expression

meta_regexp.js

var regexpMatcher = /^\/([^\/]|\\\/)+\/[$gim]*$/;

function assert(value) { return regexpMatcher.test(value); }
function isRegexp(value) { if (!assert(value)) alert("Failed " + value); }
function isNotRegexp(value) { if (assert(value)) alert("Failed " + value); }

isRegexp("/foo/");
isRegexp("/foo/gim");
isRegexp("/foo/img");

isRegexp("/snacks\\/clif/"); // which as literal is just   /snacks\/clif/ 
                             // and as an Object           new RegExp("snacks/clif")

isNotRegexp("//");
isNotRegexp("/foo/b");
isNotRegexp("/foo/bar/baz/");
isNotRegexp("/foo/bar");
isNotRegexp("///");

alert("Silence is golden!");