String.prototype.search()

search() 메서드는 정규 표현식과  이 String  객체간에 같은 것을 찾기
위한 검색을 실행한다.

str.search(regexp)

regexp

정규 표현식 객체.  non-RegExp 객체 obj 가 전달되면,  그것은  new RegExp(obj) 을 이용하여 RegExp 으로 암묵적으로 변환된다.

정규표현식과 주어진 스트링간에 첫번째로 매치되는 것의 인덱스를 반환한다.
찾지 못하면 -1 를 반환한다.

When you want to know whether a pattern is found and also its index in a string use search() (if you only want to know if it exists, use the similar test() method on the RegExp prototype, which returns a boolean); for more information (but slower execution) use match() (similar to the regular expression exec() method).

The following example searches a string with 2 different regex objects to show a successful search (positive value) vs. an unsuccessful search (-1)

var str = "hey JudE";
var re = /[A-Z]/g;
var re2 = /[.]/g;
console.log(str.search(re)); // returns 4, which is the index of the first capital letter "J"
console.log(str.search(re2)); // returns -1 cannot find '.' dot punctuation

• flags was a non standard second argument only available in Gecko : str.search(regexp, flags)
• Prior to Gecko 8.0, search() was implemented incorrectly; when it was called with no parameters or with undefined, it would match against the string 'undefined', instead of matching against the empty string. This is fixed; now 'a'.search() and 'a'.search(undefined) correctly return 0.
• Starting with Gecko 39 (Firefox 39 / Thunderbird 39 / SeaMonkey 2.36), the non-standard flags argument is deprecated and throws a console warning (bug 1142351).
• Starting with Gecko 47 (Firefox 47 / Thunderbird 47 / SeaMonkey 2.44), the non-standard flags argument is no longer supported in non-release builds and will soon be removed entirely (bug 1245801).
• Starting with Gecko 49 (Firefox 49 / Thunderbird 49 / SeaMonkey 2.46), the non-standard flags argument is no longer supported (bug 1108382).

• String.prototype.match()
• RegExp.prototype.exec()