PHP Tutorial :: Strings (I)

<?php
print "Hello, World! ";
print 'This is a demonstration of how PHP prints text strings. Print doesn\'t add any line break and the strings will be printed one following each other. You can use echo instead of print for the same purpose. ';
print 'We\'ll need to scape the single quotes when our text string contains them. ';
print ' Use \\ to scape in a string. ';
print 'And yes, we can use single or double quotes for marking strings. But double quotes admit more special characters than single quotes. ';
print nl2br("So it is time to test a line break: \n We use \\n to indicate a
line break and the nl2br() function to force the " . "browser to not ignore the whitespace created. ");
print 'We can join strings ' . 'by using the character .';
?>

<?php
print "Hello, ";
// Prints what is sent in the parameter of the form named as 'user'
print $_POST['user'];
print "!";
?>

<?php
print '<ul>
<li>Beef Chow-fun</li>
<li>Sauteed Pea Shoots</li>
<li>Soy Sauce Noodles</li>
</ul>';
?>

<?php
// $_POST['zipcode'] contains the value sent by the form named as "zipcode"
$zipcode = trim($_POST['zipcode']);
// Now $zipcode contains the value with both initial and final spaces trimmed
$zip_lenght = strlen($zipcode);
// Complains when the ZIP code doesn't has 5 characters long
if ($zip_lenght != 5) {
print "Please enter a ZIP code that is 5 characters long.";
}
?>

<?php
if (strlen(trim($_POST['zipcode'])) != 5) {
print "Please enter a ZIP code that is 5 characters long.";
}
else {
print "This ZIP code is valid, it has 5 characters long.";
}
?>

<?php
if ($_POST['email'] == 'president@whitehouse.gov') {
print "Welcome, Mr. President!";
}
?>

<?php
if (strcasecmp($_POST['email'], 'president@whitehouse.gov') == 0) {
print "Welcome, Mr. President!";
}
?>