PHP If...Else Statements
Conditional statements are used to perform different actions based on different conditions.
Conditional Statements
Very often when you write code, you want to perform different actions for
different decisions.
You can use conditional statements in your code to do this.
In PHP we have the following conditional statements:
- if statement - use this statement to execute some code only if a specified condition is true
- if...else statement - use this statement to execute some code if a condition is true and another
code if the condition is false
- if...elseif....else statement - use this statement to select one of
several blocks of code to be executed
- switch statement - use this statement to select one of many blocks of code to be executed
The if Statement
Use the if statement to execute some code only if a specified condition is true.
Syntax
| if (condition) code to be executed if condition is true; |
The following example will output "Have a nice weekend!" if the current day
is Friday:
<html>
<body>
<?php
$d=date("D");
if ($d=="Fri") echo "Have a nice weekend!";
?>
</body>
</html>
|
Notice that there is no ..else.. in this syntax. You tell the browser to execute some code only if the specified condition is true.
The if...else Statement
Use the if....else statement to execute some code if a condition is true and another code if a
condition is false.
Syntax
if (condition)
code to be executed if condition is true;
else
code to be executed if condition is false;
|
Example
The following example will output "Have a nice weekend!" if the current day
is Friday, otherwise it will output "Have a nice day!":
<html>
<body>
<?php
$d=date("D");
if ($d=="Fri")
echo "Have a nice weekend!";
else
echo "Have a nice day!";
?>
</body>
</html>
|
If more than one line should be executed if a condition is true/false, the
lines should be enclosed within curly braces:
<html>
<body>
<?php
$d=date("D");
if ($d=="Fri")
{
echo "Hello!<br />";
echo "Have a nice weekend!";
echo "See you on Monday!";
}
?>
</body>
</html>
|
The if...elseif....else Statement
Use the if....elseif...else statement to select one of several blocks of code to be executed.
Syntax
if (condition)
code to be executed if condition is true;
elseif (condition)
code to be executed if condition is true;
else
code to be executed if condition is false;
|
Example
The following example will output "Have a nice weekend!" if the current day
is Friday, and "Have a nice Sunday!" if the current day is Sunday. Otherwise it will output "Have a nice day!":
<html>
<body>
<?php
$d=date("D");
if ($d=="Fri")
echo "Have a nice weekend!";
elseif ($d=="Sun")
echo "Have a nice Sunday!";
else
echo "Have a nice day!";
?>
</body>
</html>
|
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