var s="ab";
console.log( /a?b/.test(s) );
console.log( /x?b/.test(s) );
console.log( /x?b?/.test(s) );
console.log( /x?y?/.test(s) );
Ответ:
true
true
true
true
JavaScript test | #JavaScript
JA JavaScript test @js_test · 9.67K subscribers var s="ab";
console.log( /a?b/.test(s) );
console.log( /x?b/.test(s) );
console.log( /x?b?/.test(s) );
console.log( /x?y?/.test(s) );