Web Guide UK - Web Design Tutorials

An introduction to if statements and else statements

When your interacting with php from time to time you may want to show something else depending on a condition this is very simple to do using if and if else statements.

The syntax for an if statement goes like this:

<?php
 
if (condition) { 
 
//do something
 
}
?>

then this can include an else statement

<?php
 
if (condition) {
 
//do something
 
} else {
 
//do something else
 
}
?>

This can be expanded further using an ifelse statement:

<?php
 
if (condition1) {
 
//do something
 
} elseif (condition2) {
 
//do something else
 
} else {
 
// do something diffrent
 
}
?>

In the first example if (condition) { means in condition is true then do what ever is between the brackets { } in this case it was only a comment.

Then next example was in first condition is not true then do the else again this was only a comment.

The third example was if condition1 is not true then do condition 2 but if thats not true either then do the else.

Using if statement can be really useful for example you could have a different welcome message depending on what someone fills in on a form.

Lets make a simple form:

<?php
<form method="post" action="<?php $_SERVER['PHP_SELF'];?>">
Name:<input type="text" name="name"/>
<input type="submit" name="submit" value="submit" />
</form>
?>

This form asks for a name and has a submit button to send to form. The form will reload the page once it has being sent using the php global variable

<?php
$_SERVER['PHP_SELF']
?>

Now we will use an if statement to see if the form has being submitted:

<?php
if(isset($_POST['submit'])){
?>

If the form has been submitted we then get the name from the form using

<?php
$name   = $_POST['name'];
?>

We now check to see what the name is and show a message

<?php  
if ($name == 'dave'){ // if name is equal to dave print message
 
    echo "<p>Dave is your name</p>";
 
    } elseif ($name == 'tony') { if name is equal to tony print message
 
    echo "<p>Tony is your name</p>";
 
    } else { if not equal to dave or tony then print their name
 
    echo "<p>your name is $name</p>";
    }
?>

Now we close the bracket for if the form has being submitted with a closing bracket ‘}’

Here’s the full script:

<?php
if(isset($_POST['submit'])){
 
$name   = $_POST['name'];
 
if ($name == 'dave'){ // if name is equal to dave print message
 
    echo "<p>Dave is your name</p>";
 
    } elseif ($name == 'tony') { if name is equal to tony print message
 
    echo "<p>Tony is your name</p>";
 
    } else { if not equal to dave or tony then print their name
 
    echo "<p>your name is $name</p>";
    }
 
}
?>
 
 
<form method="post" action="<?php $_SERVER['PHP_SELF'];?>">
Name:<input type="text" name="name"/>
<input type="submit" name="submit" value="submit" />
</form>
?>

This is a very basic example of using if statements to give you a simple example of how to use them.