Basics Flashcards
What is console.log used for
Writing messages to the console log. Useful for debugging.
for example console.log(“first script called”)
How is JS integrated in the header
<script src=”script.js” type=”text/javascript”></script>
Where are the 3 areas where javascript code can be positioned?
1) As a separate file and reference in the header
2) With in the header area
3) Within the <body> area
How is JS integrated in the header area?
<script type=”text/javascript”></script>
How is JS integrated in the body area?
<script type=”text/javascript”></script>
How are single line comments added in JS?
//
How are multiline comments added in JS
/*………
…..*/
How are functions defined in JS?
Functions are defined by the keyword FUNCTION. Followed by the function name and ( ).
The actual function is enclosed in { }
Example
function bob( ) {
actual function goes here }
How would function bob be called after it is defined?
bob( );
What 9 keywords cannot be used as function names?
switch
case
break
if
else
for
function
try
catch
How is a value returned from a function?
var added = add(5,5);
function add(a,b) {
var y = a + b;
return y;
};
added would = 10
How are arguments provided to a function?
Within the function call parentheses
bob(var1,var2)
How is each element of a web page referenced
As an object
How is a new object created?
Var myobj = new Myobject( );
Name 5 of the predefined objects
Window
Date
Math
String
Array
How are object methods and attributes referenced?
With a dot.
e.g oDate.getDate( )
Name the 2 special objects that do not require the dot reference
Window and Console
How are object context objects accessed?
Use “this”
this.objcont name
How are variables pre-typed in JS?
They aren’t. All variables are assigned at runtime based on their content
What is the difference in JS between var mynum = 123;
and var mynum = “123”;
123 is created as an integer
“123” is created as a string
Once created, a variables type cannot change
False. It can change based on new contents
Var is a required keyword when working with a variable in JS
False
var myvar = 3;
is equal to
myvar = 3;
What happens if the VAR keyword is ommitted within a function?
The variable becomes a global variable
In JS,
var myVar = 123;
is equivelent to
var myvar = 123;
False. JS is case dependent.
