deeply love javascript and ajax

getElementByTagName

2008-09-14T06:42:00.000-07:00

return an array with element with tag name, with order they appear in the page

ex:

document.getElementByTagName("div")

innerHTML

2008-09-14T05:51:00.000-07:00

the content of tag element

usage: get or change the content of element

ex:

document.getElementById("test").innerHTML= "change";

regular expression in javascript

2008-09-14T05:38:00.000-07:00

syntax:

/ expression /

. : match any character other than newline

\s: match a whitespace character

\d: match number

\w: match alphanumeric character

^: beginning of the string

$: end of the string

\: escape character

quantifiers:

* : o or more times

+: 1 or more times

?: o or 1 time

{ n} : n times

{min, max}:

[abc]: a or b or c

regular expression is a RegExp object

how to use:

ex:

var key= /\d/;

if( key.test( "32") )

{

alert("matched");

}

control logic ( if & switch)

2008-08-27T09:27:00.000-07:00

switch , case, break , default:
the same as C syntax

if , else :
the same as C syntax

comment

2008-08-27T09:20:00.000-07:00

single line: //

multiple lines: /* and */

prompt

2008-08-14T10:20:00.000-07:00

let user enter data

ex:

prompt("what is your name", "insert name here");

import javascript into html

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body's event

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onload:

when page is loaded

onresize:

when browser is resized

style object

2008-08-14T09:31:00.000-07:00

each element of web page has a style object

style.height:

style.width:

document object

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document.body.clientHeigth:

client window height

document.body.clientWidth:

client window width

document.getElementById("elementName")

document.cookie:

set cookie:

ex:

document.cookie="name1=peter;expires=1/1/2000;";

how to clear cookie:

set it value to "" & expiration data to -1

string method

2008-06-12T07:16:00.000-07:00

indexOf()

find the pattern in the string

ex:

"abcdef".indexof("bc");

getElementById

2008-06-12T07:04:00.000-07:00

getElementById

get html element

ex:

html element:

input type="text", id="test", name="abc"

javascript:

document.getElementById("test").value

access data from value

math methods

2008-06-12T07:02:00.000-07:00

NaN:

not a number

parseInt():

convert test to integer

ex:

parseInt("1");

parseFloat()

isNaN():

ex:

var a=3;

isNaN(a);

toFixed():

ex:

a=3.333;

a.toFixed(2);

---> a=3.33

alert

2008-06-12T07:00:00.000-07:00

show an alert box:

ex:

alert("hello");

variable , constant, function

2008-06-12T06:44:00.000-07:00

variable:

ex:

var test=300;

constant:

ex:

const TEST= 300;

function:

ex:

function test() {

}

call two methods:

ex: