JavaScript String substring() Method

The string.substring() is an inbuilt function in JavaScript that is used to return the part of the given string from the start index to the end index. Indexing start from zero (0).

Syntax:

string.substring(Startindex, Endindex)

Parameters: Here the Startindex and Endindex describe the part of the string to be taken as a substring. Here the Endindex is optional.

Return value: It returns a new string that is part of the given string.

JavaScript code to show the working of string.substring() function:

Example 1: This example prints the values of the sub-strings from a variable string in the console, here we use starting index value.

javascript

const str = "GeeksforGeeks";
const result = str.substring(8);
console.log(result);

Output

Geeks

Example 2: In this example, we are using starting and last index values.

Javascript

const str = "GeeksforGeeks";
const result = str.substring(5, 8);
console.log(result);

Output

for

Example 2: Index always starts with 0. If still, we take an index as negative, it will be considered zero and the index can’t be in fractions if it is found so, it will be converted into its just a lesser whole number.

javascript

// Taking a string as letiable
let string = "geeksforgeeks";
a = string.substring(-1)
b = string.substring(2.5)
c = string.substring(2.9)
 
// Printing new string which are
// the part of the given string
console.log(a);
console.log(b);
console.log(c);