JavaScript: Remove last character from string

In this article I want to show you how you can remove the last character from any string with the help of JavaScript.

Before I start with the explanations, let's first take a look at the code required for this. Here is how to do it:

var strold = '1,2,3,';
var strnew = strold.substr(0, strold.length - 1);
alert(strnew);  // output: '1,2,3'

In the example, we have specified a string "strold", which contains a comma too much at its end, that we want to remove. The new resulting string should be later stored in the variable "strnew".

We are using the method substr(), which allows us to return parts of a string. Substr() takes two parameters: The first parameter is the position of the start (0 for the first character) and the second parameter is the length of our substring (number of characters).

In order to delete the last character, we proceed as follows: We want to extract a substring starting from the first character of the original string. So our first parameter is 0, because in JavaScript, the first character is the 0th character. From this character on, we want to keep as many characters as the string is long up to one character at the end. So, we can get the length of the old string with "strold.length" and simply subtract 1.

Delete first and last character

To illustrate this, here is just another example in which we want to delete the first and the last character from a string in JavaScript:

var strold = '12345';
var strnew = strold.substr(1, strold.length - 2);
alert(strnew);  // output: '234'

If we also do not want to keep the first character of the string, we have to start at 1 rather than at 0 (the first character is 0, the second character is 1). Thus, our first parameter is 1, so that we can cut the first letter off the string.

From this character on, we want to keep as many characters as the string length minus 2. If we would subtract 1 again as in the last example, we would keep our last character here, because this time, we are starting one character from the beginning. The second parameter is therefore not the position up to which we want to cut, but the number of characters counted from the position that was specified as the first parameter.