programming-for-dummies

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Using Operators
VariableName can be any descriptive name. Because JavaScript is a casesensitive
language, it treats My2008Tax as a completely different variable
than my2008tax. Some programmers use uppercase letters to make variable
names easier to find whereas others use all lowercase. To declare multiple
variables, just cram them all on a single line, separated by a comma, such as
var VariableName1, VariableName2, VariableName3;
Using Operators
The three types of operators used are mathematical, relational, and logical.
Mathematical operators calculate numeric results such as adding, multiplying,
or dividing numbers, as shown in Table 3-1.
Table 3-1
Mathematical Operators
Mathematical Operator Purpose Example
+ Addition 5 + 3.4
- Subtraction 203.9 – 9.12
* Multiplication 39 * 146.7
/ Division 45 / 8.41
% Modula division (returns the remainder) 35 % 9 = 8
The + operator can also concatenate two strings together, such as “Hi
there,” + “good looking.” This would create one string that contains
“Hi there, good looking.”
Relational operators compare two values and return a True or False value.
The six comparison operators available are shown in Table 3-2.
Table 3-2
Relational Operators
Relational Operator Purpose
== Equal
!= Not equal
< Less than
Greater than
>= Greater than or equal to