BASICS:
Including JavaScript in an HTML page
<script type = “text/javascript>js code here </script>
Call an External JavaScript File
<script src=”myscript.js”></script>
Including comments
//simngle line comoments
/*multi line comments*/
VARIABLES: (var,const,let)
var
Can be reassigned but only accessed within the function
const
Cannot be reassigned and not accessible before they appear within the code
let
Similar to const, however, it can be reassigned but not re-declared.
DATA TYPES:
numbers
var age = 20
text(string)
var a =”sid”
boolean
var b = true
constant numbers
const pi=3.14
object
var name -{
firstName:”sid”
lastName:”pandey”
}
ARRAYS:
var fruit = [“banana” , “apple” , “pear”]
methods:
concat() – for concating the arrays
indexOf() – retures the position of element in array
join() – combine elements into single strings
lastindex() – gives last elemet position
pop() – removes the last element
push() – add new element at end
reverse() – revere the oder of the element
shift() – remove the first element of an array
slice() – pulls a copy of a portion of an array
sort() – sorts the elements alphabetically
splice() – add elements in a specified way and position
toString() – converts elemets into strings
unshift() – adds a new elemets to the beginning
valaueOf() – retuns the primitive value of the specified object
FUNCTIONS:
function name(parameter 1, parameter 2,…){
what the function does
}
alert()
output data in an alert box in the browser window
confirm()
opens up ayes/no dialog and returns true/false depending on user click
console.log()
writes info to the browser console, good for debugging purposes
document.write()
write to the HTML document
prompt()
creates a dialogue for the user’s input
LOOPS:
for()
for (befor loop; conditon for loop;exectue after loop){
write what to do during the loop
}
while()
while(condition for loopo)[
write ehat to do during the loop
reinitialization
}
do while()
initialization
do(){
write ehat to do during the loop
reinitialization
} while (condition for loop)
