Take some part of the this string to make a smaller string (substring).


If a string has a part of it copied as another string, it is called a substring. A new substring is made by copying from the first string at some starting place. Also, the substring copies just the amount of characters you want from the first string.

You could make a new string that just has the word "there" from a bigger string that says "Hello there!!!". To do that, the substring is copied from the character position of 6 in the first string and 5 characters are copied. It’s done like this:

let there = "Hello there!!!".substr(6, 5);

If you want to have the substring copy to the end of the first string, you just use the starting position without any length number. This will copy all of the first string beginning at position 6. The substring will say "there!!!" in this case.

let there = "Hello there!!!".substr(6);


  • start: a number which is the position to start copying from in this string.
  • length: a number which is the amount of characters to copy from this string. If length is left out, the rest of this string is copied beginning at start. If length is 0 or less, a string with nothing in it is made.


  • a new string which is some part of the this string.


Copy the nouns from the sentence into two smaller strings.

let sentence = "The mountains have snow.";
let mountains = sentence.substr(4, 9);
let snow = sentence.substr(19, 4);

See also

char at