XML Attribute Values Must be Quoted
XML elements can have attributes in name/value pairs just like in HTML.
In XML, the attribute values must always be quoted.
Study the two XML documents below. The first one is incorrect, the second is correct:
<note date=12/11/2007>
<to>Tove</to>
<from>Jani</from>
</note>
<note date="12/11/2007">
<to>Tove</to>
<from>Jani</from>
</note>
The error in the first document is that the date attribute in the note element is not quoted.
Entity References
Some characters have a special meaning in XML.
If you place a character like "<" inside an XML element, it will generate an error because the parser interprets it as the start of a new element.
This will generate an XML error:
<message>if salary < 1000 then</message>
To avoid this error, replace the "<" character with an entity reference:
<message>if salary < 1000 then</message>
There are 5 predefined entity references in XML:
< < less than
> > greater than
& & ampersand
' ' apostrophe
" " quotation mark
Note: Only the characters "<" and "&" are strictly illegal in XML. The greater than character is legal, but it is a good habit to replace it.
Comments in XML
The syntax for writing comments in XML is similar to that of HTML.
<!-- This is a comment -->
White-space is Preserved in XML
HTML truncates multiple white-space characters to one single white-space:
HTML: Hello Tove
Output: Hello Tove
With XML, the white-space in a document is not truncated.
XML Stores New Line as LF
In Windows applications, a new line is normally stored as a pair of characters: carriage return (CR) and line feed (LF). In Unix applications, a new line is normally stored as an LF character. Macintosh applications also use an LF to store a new line.
XML stores a new line as LF.
XML Attribute Values Must be Quoted
XML Syntax Rules
XML Syntax Rules
All XML Elements Must Have a Closing Tag
In HTML, elements do not have to have a closing tag:
<p>This is a paragraph
<p>This is another paragraph
In XML, it is illegal to omit the closing tag. All elements must have a closing tag:
<p>This is a paragraph</p>
<p>This is another paragraph</p>
Note: You might have noticed from the previous example that the XML declaration did not have a closing tag. This is not an error. The declaration is not a part of the XML document itself, and it has no closing tag.
XML Tags are Case Sensitive
XML tags are case sensitive. The tag <Letter> is different from the tag <letter>.
Opening and closing tags must be written with the same case:
<Message>This is incorrect</message>
<message>This is correct</message>
Note: "Opening and closing tags" are often referred to as "Start and end tags". Use whatever you prefer. It is exactly the same thing.
XML Elements Must be Properly Nested
In HTML, you might see improperly nested elements:
<b><i>This text is bold and italic</b></i>
In XML, all elements must be properly nested within each other:
<b><i>This text is bold and italic</i></b>
In the example above, "Properly nested" simply means that since the <i> element is opened inside the <b> element, it must be closed inside the <b> element.
XML Documents Must Have a Root Element
XML documents must contain one element that is the parent of all other elements. This element is called the root element.
<root>
<child>
<subchild>.....</subchild>
</child>
</root>
CreateDirectory In Visual baisc
CreateDirectory In Visual baisc
Imports System.IO
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
If Not TextBox1.Text = String.Empty Then
Dim dirinf As DirectoryInfo
dirinf = New DirectoryInfo(TextBox1.Text)
Try
dirinf.Create()
Catch ex As IOException
MsgBox("tak dapat create directory" & vbCrLf & ex.Message)
Catch ex1 As UnauthorizedAccessException
MsgBox(" tak boleh create directory" & TextBox1.Text)
End Try
'cara kedua
'Directory.CreateDirectory(TextBox1.Text)
End If
End Sub
Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
If Not TextBox1.Text = String.Empty Then
Dim dirinf As DirectoryInfo
dirinf = New DirectoryInfo(TextBox1.Text)
Try
dirinf.Delete()
Catch ex As IOException
MsgBox("tek boleh delete")
End Try
'cara kedua
'Directory.Delete(TextBox1.Text)
End If
End Sub
End Class
how to change button color in visual basic
change button color in visual basic
Public Class Form1
Private Sub Button1_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Button1.MouseMove
Me.Button1.BackColor = Color.Blue
Me.Button1.ForeColor = Color.Gold
End Sub
Private Sub Form1_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Me.MouseMove
Me.Button1.BackColor = Color.Gray
Me.Button1.ForeColor = Color.Black
End Sub
End Class
PHP Variables
PHP Variables
Variables in PHP
Variables are used for storing values, like text strings, numbers or arrays.
When a variable is declared, it can be used over and over again in your script.
All variables in PHP start with a $ sign symbol.
The correct way of declaring a variable in PHP:
$var_name = value;
New PHP programmers often forget the $ sign at the beginning of the variable. In that case it will not work.
Let's try creating a variable containing a string, and a variable containing a number:
<?php
$txt="Hello World!";
$x=16;
?>
PHP is a Loosely Typed Language
In PHP, a variable does not need to be declared before adding a value to it.
In the example above, you see that you do not have to tell PHP which data type the variable is.
PHP automatically converts the variable to the correct data type, depending on its value.
In a strongly typed programming language, you have to declare (define) the type and name of the variable before using it.
In PHP, the variable is declared automatically when you use it.
Naming Rules for Variables
* A variable name must start with a letter or an underscore "_"
* A variable name can only contain alpha-numeric characters and underscores (a-z, A-Z, 0-9, and _ )
* A variable name should not contain spaces. If a variable name is more than one word, it should be separated with an underscore ($my_string), or with capitalization ($myString)
PHP String Variables
PHP String Variables
String Variables in PHP
String variables are used for values that contain characters.
In this chapter we are going to look at the most common functions and operators used to manipulate strings in PHP.
After we create a string we can manipulate it. A string can be used directly in a function or it can be stored in a variable.
Below, the PHP script assigns the text "Hello World" to a string variable called $txt:
<?php
$txt="Hello World";
echo $txt;
?>
The output of the code above will be:
Hello World
The Concatenation Operator
There is only one string operator in PHP.
The concatenation operator (.) is used to put two string values together.
To concatenate two string variables together, use the concatenation operator:
<?php
$txt1="Hello World!";
$txt2="What a nice day!";
echo $txt1 . " " . $txt2;
?>
The output of the code above will be:
Hello World! What a nice day!
If we look at the code above you see that we used the concatenation operator two times. This is because we had to insert a third string (a space character), to separate the two strings.
The strlen() function
The strlen() function is used to return the length of a string.
Let's find the length of a string:
<?php
echo strlen("Hello world!");
?>
The output of the code above will be:
12
The length of a string is often used in loops or other functions, when it is important to know when the string ends. (i.e. in a loop, we would want to stop the loop after the last character in the string).
The strpos() function
The strpos() function is used to search for character within a string.
If a match is found, this function will return the position of the first match. If no match is found, it will return FALSE.
Let's see if we can find the string "world" in our string:
<?php
echo strpos("Hello world!","world");
?>
The output of the code above will be:
6
The position of the string "world" in our string is position 6. The reason that it is 6 (and not 7), is that the first position in the string is 0, and not 1.
JavaScript in (head)
JavaScript in (head)
The example below calls a function when a button is clicked:
<html>
<head>
<script type="text/javascript">
function displayDate()
{
document.getElementById("demo").innerHTML=Date();
}
</script>
</head>
<body>
<h1>My First Web Page</h1>
<p id="demo"></p>
<button type="button" onclick="displayDate()">Display Date</button>
</body>
</html>
Scripts in <head> and <body>
You can place an unlimited number of scripts in your document, and you can have scripts in both the body and the head section at the same time.
It is a common practice to put all functions in the head section, or at the bottom of the page. This way they are all in one place and do not interfere with page content.
A message box when page opens (Javascript Code)
A message box when page opens (Javascript Code)
You can bring a message box or a alert a window which tell something to user at the first when page opens
this script got from http://codes-free.blogspot.com/ coded by:Codes
<html>
<head>
<script language="javascript" type="text/javascript">
alert("Welcome to my site")
</script>
</head>
</html>
<font face="Tahoma"><a target="_blank"
href="http://codes-free.blogspot.com//"><span style="font-size:
8pt; text-decoration: none">JavaScript Free
Code</span></a></font> Read More »»
CSS Syntax
CSS Syntax
CSS Example
CSS declarations always ends with a semicolon, and declaration groups are surrounded by curly brackets:
p {color:red;text-align:center;}
To make the CSS more readable, you can put one declaration on each line, like this:
p
{
color:red;
text-align:center;
}
CSS Comments
Comments are used to explain your code, and may help you when you edit the source code at a later date. Comments are ignored by browsers.
A CSS comment begins with "/*", and ends with "*/", like this:
/*This is a comment*/
p
{
text-align:center;
/*This is another comment*/
color:black;
font-family:arial;
}
CSS Introduction
CSS Introduction
What is CSS?
* CSS stands for Cascading Style Sheets
* Styles define how to display HTML elements
* Styles were added to HTML 4.0 to solve a problem
* External Style Sheets can save a lot of work
* External Style Sheets are stored in CSS files
Styles Solved a Big Problem
HTML was never intended to contain tags for formatting a document.
HTML was intended to define the content of a document, like:
<h1>This is a heading</h1>
<p>This is a paragraph.</p>
When tags like <font>, and color attributes were added to the HTML 3.2 specification, it started a nightmare for web developers. Development of large web sites, where fonts and color information were added to every single page, became a long and expensive process.
To solve this problem, the World Wide Web Consortium (W3C) created CSS.
In HTML 4.0, all formatting could be removed from the HTML document, and stored in a separate CSS file.
All browsers support CSS today.
CSS Saves a Lot of Work!
CSS defines HOW HTML elements are to be displayed.
Styles are normally saved in external .css files. External style sheets enable you to change the appearance and layout of all the pages in a Web site, just by editing one single file!
Read More »»
ASP Forms and User Input
ASP Forms and User Input
User Input
The Request.QueryString and Request.Form commands are used to retrieve user input from forms.
<form method="get" action="simpleform.asp">
First Name: <input type="text" name="fname" /><br />
Last Name: <input type="text" name="lname" /><br /><br />
<input type="submit" value="Submit" />
</form>
Request.QueryString
The Request.QueryString command is used to collect values in a form with method="get".
Information sent from a form with the GET method is visible to everyone (it will be displayed in the browser's address bar) and has limits on the amount of information to send.
If a user typed "Bill" and "Gates" in the HTML form above, the URL sent to the server would look like this:
Assume that "simpleform.asp" contains the following ASP script:
<body>
Welcome
<%
response.write(request.querystring("fname"))
response.write(" " & request.querystring("lname"))
%>
</body>
The browser will display the following in the body of the document:
Request.Form
The Request.Form command is used to collect values in a form with method="post".
Information sent from a form with the POST method is invisible to others and has no limits on the amount of information to send.
If a user typed "Bill" and "Gates" in the HTML form above, the URL sent to the server would look like this:
Assume that "simpleform.asp" contains the following ASP script:
<body>
Welcome
<%
response.write(request.form("fname"))
response.write(" " & request.form("lname"))
%>
</body>
The browser will display the following in the body of the document:
Form Validation
User input should be validated on the browser whenever possible (by client scripts). Browser validation is faster and reduces the server load.
You should consider server validation if the user input will be inserted into a database. A good way to validate a form on the server is to post the form to itself, instead of jumping to a different page. The user will then get the error messages on the same page as the form. This makes it easier to discover the error. Read More »»
ASP Procedures
ASP Procedures
<html>
<head>
<%
sub vbproc(num1,num2)
response.write(num1*num2)
end sub
%>
</head>
<body>
<p>Result: <%call vbproc(3,4)%></p>
</body>
</html>
Insert the <%@ language="language" %> line above the <html> tag to write the procedure/function in another scripting language:
<%@ language="javascript" %>
<html>
<head>
<%
function jsproc(num1,num2)
{
Response.Write(num1*num2)
}
%>
</head>
<body>
<p>Result: <%jsproc(3,4)%></p>
</body>
</html>
Read More »»
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