3D Game Programming

Strings

Strings in JavaScript are kind of boring. You can really only join two strings

into larger strings. What is interesting is that the plus operator is what joins

them together. Try the following in the JavaScript console.

varstr1 ="Howdy";

varstr2 ="Bob";

str1 +" "+ str2;

// "Howdy Bob"

Pretty crazy, isn’t it? Given that there are no multiplication and division keys

on most keyboards, there definitely are no stick-two-strings-together keys.

So JavaScript gets lazy and uses the plus sign again.

What do you suppose happens if you try to join a string and a number? Well,

give it a try:

varstr ="The answer to 7 + 4 is ";

varanswer = 7 + 4;

str + answer;

Try This Yourself

Do this and check it in the JavaScript console!

The result is that, when combining a string and a number, JavaScript will

treat the number as a string:

varstr ="The answer to 7 + 4 is ";

varanswer = 7 + 4;

str + answer;

// "The answer to 7 + 4 is 11"

Booleans

There is not much to a Boolean. It is either true or false. It is possible to convert

Booleans with the not operator. In JavaScript, the exclamation point is the not

operator:

varyes = true;

varthe_opposite = !yes;

varthe_opposite_of_the_opposite = !!yes;

yes;

// true

the_opposite;

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Changing Things • 73

Prepared exclusively for Michael Powell