get the first few letrer of a string js code example

Example 1: javascript get first 10 characters of string

var str = "Hello world That is reallly neat!";
var res = str.substring(0, 5);//get first 5 chars

Example 2: js substring first 4 numbwe

mystring = "9862 ....... -pack size 1 - SST Unspun Label (Roll) CAT#: 9862";

mystring = mystring.substring(0, 4);

alert(mystring.trim());