Learning PHP, MySQL, and JavaScript

Explicit Casting

Unlike PHP, JavaScript has no explicit casting of types such as (int) or (float). Instead, when you need a value to be of a certain type, use one of JavaScript’s built-in functions, shown in Table 15-6.

Table 15-6. JavaScript’s type-changing functions

Change to type	Function to use
Int, Integer	parseInt()
Bool, Boolean	Boolean()
Float, Double, Real	parseFloat()
String	String()
Array	split()

So, for example, to change a floating-point number to an integer, you could use code such as the following (which displays the value 3):

n = 3.1415927
i = parseInt(n)
document.write(i)

Or you can use the compound form:

document.write(parseInt(3.1415927))

That’s it for control flow and expressions. The next chapter focuses on the use of functions, objects, and arrays in JavaScript.