JavaScript Regular Expression (REGEXP)

What is RegExp

RegExp is a pattern used to describe what to retrieve.

Define RegExp

1 var New REGEXP ("mode");

Methods for RegExp objects

RegExp objects have 3 methods: Test (), exec (), compile ()

Test ()

Retrieves the value specified in the string. The return value is TRUE or False

1 var New REGEXP ("E"); 2 document.write (patt.test ("I am a Student"); 3 // return value 4 true

EXEC ()

Retrieves the value specified in the string. The return value is the found value, and null is returned if no match is found.

1 var New REGEXP ("E"); 2 document.write (patt.exec ("I am a student."); 3 //return value 4 E

A second parameter can be set to set the retrieval

G: Global Search

I: Perform a case insensitive match

M: Perform multi-line matching

1 var New REGEXP ("E", "G"); 2  Do {3     result = patt.exec ("I am a student in the university"); 4     document.write (result); 5  while NULL ); 6 // Execution Results 7 Eeenull

Compile ()

Used to change regexp.

That is, you can change the retrieval mode, or you can add or remove a second parameter.

1 var New REGEXP ("E"); 2 document.write (patt.test ("I am a Student"); 3 patt.compile ("B"); 4 document.write (patt.test ("I am a Student"); 5 // Output Results 6 TrueFalse

Summary from: http://www.w3school.com.cn/js/js_obj_regexp.asp

JavaScript Regular Expression (REGEXP)