HTML5 Data and Services Cookbook

Padding numbers

We are sometimes faced with the need to pad numbers to a certain range. For example, suppose we want to display a number in five possible digits, such as 00042. One obvious solution would be to use the iterative approach and prepend characters, but there are a few cleaner solutions.

Getting ready

First, we need to take a look at some of the functions that we are going to use. Let's take a look at the Array.join(separator) method that can be applied to create joined text from a list of elements:

new Array('life','is','life').join('*')

This will result in "life*is*life" that shows fairly simple elements that are joined with a given separator. Another method that is of interest is Array.slice(begin[, end]) that returns a copy of a portion ...