JS IndexOf method, LastIndexOf method, substring method

Returns the character position for the first occurrence of a substring within a string object.

Strobj.indexof (substring[, StartIndex])

Parameters
Strobj

Required option. A String object or text.

SubString

Required option. The substring to find in the string object.

Starindex

Options available. An integer value that indicates the index in which to start the lookup within a String object. If omitted, it is looked up from the beginning of the string.

Description
The IndexOf method returns an integer value that indicates the starting position of the substring of the string object. If no substring is found, returns-1.

If the startindex is a negative number, the startindex is treated as zero. If it is larger than the maximum character position index, it is considered to be the largest possible index.

Performs a lookup from left to right. Otherwise, the method is the same as LastIndexOf.

Example
The following example illustrates the use of the IndexOf method.

function Indexdemo (str2) {
var str1 = "Babebibobubabebibobu"
var s = str1.indexof (STR2);
return (s);
}

The LastIndexOf method returns the position of the last occurrence of the substring, as opposed to the indexof.


Substring method

str=str.substring (int beginindex); intercepts the string of STR from the first letter length to Beginindex, assigning the remaining string to STR;

str=str.substring (int beginindex,int endindex); intercepts the string from the beginning of the beginindex to the end of the Endindex in STR and assigns it to STR;