In Class Notes // Review

Attaching an External Script
The advantage is that you have 1 file that effects multiple pages, this makes editing easier.

1. The extension has to be .js

2. you add src:
<script type="text/javascript" src="myExternal.js"></script>

3. make sure there is nothing between the <script> tags


The order that you attach scripts is important.

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Trouble Shooting
Unfortunately the browsers interpret the scripts differently. The different browsers have tools to help you figure out errors.

Firefox:
Tools >> Error Console
Usually the information presented by the console is useless, but it gives you an idea of the area that is probably causing problems.

Firebug:
More usefull

Webdeveloper: (just for Firefox)
A toolbar extension that is really helpful, in particular with jQuery.

Safari:
Develop >>> Show Error Console


--------------------------REVIEW of the  READING ASSIGNMENT-------------------------

Operators

Operators are Symbols that allow us to manipulate/modify data.

= assignment operator

 (set to the value of)

 Math Operators

+ - * /

Order of operations:
PEMDAS aka Please Excuse My Dear Aunt Sally
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

M and D have the same weight
A and S have the same weight
so these are performed left to right

(PEMDAS will be on the test)  
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Combining Strings
Concatenation
+ the operator use to concatenate
(this is not the same as the mathematical operator + )

var lastName = "Fartyfatkins";
var firstName = "Hugo";


var theName = firstName + ' ' + lastName;

document.write(theName);

The Point this is to show that you should not have the ' ' (space) in the variable declaration.
var lastName = "Fartyfatkins ";    BAD 


Fixing - Automatic Type Conversion
Number(variable) +Number(variable2)

Changing the Values in Variables 

score = 0;

score = score + 3;

The point is that everything that happens on the right, gets dumped into the left.

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