[Learning]#13 JS: Intro to Data, Variables, Operators

Data: Number, String, Boolean

• Number: e.g. 7, 17
• String: consist of quotation marks and semicolon, e.g. “this is a string”;
• Boolean: e.g. true, false

Variables

A variable is a container for storing data or values.
*Please note that it displays as the order we code.

Example

var x; → let's declare the variable as x.
x=17; → and we start to store value into the variable. 
alert(x); 
x="value";
alert(x);
var y=true;

Operators

Operators is like math formulas, consisting of various characters.
Let’s explain the formulas and terms by examples…

When we write

3+5; → Arithmetic operators
alert(3+5);

=> The result is 8.

var result=3*5; → Assignment operators
alert(result);

=> The result is 15.

Follow the last operator

result++; → increment (++) operators. It means the result has to plus 1, which can also be written as “result+1;”
alert(result);

=> The result is 16.

4<3; → Comparison operators.
result=4<3; 
alert(result);

=> The boolean is “true.” If we write 4<3, the boolean is “false.”

var data=3;
result=data*data;
alert(result);

=> The result is 9.

alert(data);

=> The result is 3.

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