Variables
How does a program keep an internal state? How does it remember things? We have seen how to produce new values from old values, but this does not change the old values, and the new value has to be immediately used or it will dissipate again. To catch and hold values, JavaScript provides a thing called a variable.
var caught = 5 * 5;
A variable always has a name, and it can point at a value, holding on to it. The
previous statement creates a variable called caught
and uses it to grab
hold of the number that is produced by multiplying 5
by 5
.
After a variable has been defined, its name can be used as an expression that produces the value it holds. Hereâs an example:
var ten = 10;
ten * ten;
â 100
The word var
is used to create a new variable. ...
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