JavaScript: String Manipulation Functions

Example

Concatenation

var S1 = "Customer"; var S2 = "123456";  var S3 = S1 + " " + S2 + "could not be found";
 
puts Customer 123456could not be found in variable S3. 

IndexOf – finds first occurrence of a string in a string

/*        012345678901 */ var S1 = "ABCDHELLOABC"; var pos = S1.indexOf("HELLO");
 
will put the number 4 into variable pos.  

lastIndexOf - finds last occurrence of a string in a string

/*        012345678901 */ var S1 = "ABCDHELLOABC"; var pos = S1.lastIndexOf("AB");
 
will put the number 9 into variable pos.  

charAt – returns the character at a specific position in a string

/*        012345678901 */ var S1 = "ABCDHELLOABC"; var S2 = S1.charAt(4); var S3 = S1.charAt(9);
 
will put "H" into S2 and "A" into S3.

length – returns the length of a string

/*        012345678901  */ var S1 = "ABCDHELLOABC"; var I  = S1.length;
 
will put the number 11 into variable I.

substring – returns the substring of string using a starting and ending point.

/*       01234567789  */ var a = "Hello World"; var b = a.substring(4,8);
 
will put "o Wor" into b.
 

substr – returns the substring of a string using a starting position and a length

/*       01234567789  */ var a = "Hello World"; var b = a.substr(2,3);
 
will put "llo" into b.
 

toLowerCase – returns the lowercase of string

var a = "Hello World"; var b = a.toLowerCase();
 
will put "hello world" into b.
 

toUpperCase – returns the uppercase of a string

var a = "Hello World"; var b = a.toUpperCase();
 
will put "HELL WORLD" into b.