Day 027 - Numbers and Strings

In Day 021, we used the following code.

$('ul li').eq(3).css('color', 'green');

And in the demo for Day 025.

console.log('14 % 5 = ' + 14 % 5);

Notice what's going on with '. Wrapping a number in ' will convert it to a string.

Have look a at this demo.

var a = '10';
var b = 10;

$('p.concatenate').text(a + b);

Here you're setting two variables:

a as a string.

b as a number.

Then calling jQuery, searching the DOM for a p tag, with a class of Number and applying some text which is the value of a + b.

In this instance as a is a string and b a Number, rather than the expected 10 + 10 value being added together to give us 20 it will concatenate the values together to give us 1010.

So, what if you did want to add these values rather than concatenating them? It's possible to convert the string to a Number by adding Number and wrapping the variable in ( ).

$('p.addition').text(Number(a) + b);

Call jQuery, search for a p tag with a class of addition add the text of the value of the variable a as a Number, now add that to the value of the variable b giving you 20.

Hey presto!