Basically string is used to hold the data in text form . Mostly used operation on string is to check the length of string , to concatenate with the help of + and += ,check for substring with the help of indexOf method and extract substring with the substring method .
Syntax ->
String(parameter)
new String(parameter)
Parameter ->
It is used to converted anything to a string .
Now if you want to access an specific character in a string , then you can access with the help of charAt method :
Example :

return 'mukesh' . charAt(2); // It will return "k"

Compare String With the help of strcmp() method you can compare the string .
Example :

var fname = "mukesh";<br>
var lname = "Tomar"<br>
var c =  strcmp(fname , lname); // it will return true and false<br><br>

Methods In Strings :->
1) String.fromCharCode() -> It return a string created by Unicode Values .
2) String.length() -> It will return the length of a String .
' 3) String.CharAt() -> It will return the character at the specified index .
4) String.concat() -> It will return the string after combine the text of two strings and return a new string .
5) String.includes() -> It will return the string after finding within the another string .
6) String.indexOf() -> It will return the index(start from the starting index) of a string.
7) String.lastIndexOf() -> It will return the index(start from the ending index) of a string.
8) String.match() -> To match a string it is used a regular expression against a string .
9) String.split() -> It is used to seperate a string from original string string into an array and return a substirng .
10) String.slice() -> It is used to extract a section of a string and return a new string .