PHP, если вход пуст
$a = empty($a) ? "Default value" : $a;
Smiling Salamander
$a = empty($a) ? "Default value" : $a;<?php
function formWasPosted()
{
return array_key_exists( 'comp', $_POST );
}
// -------
function validate( &$errors )
{
if ( $_POST['comp'] == '' )
{
$errors['comp'] = 'cannot be blank';
}
return count( $errors ) == 0;
}
// -------
function getError( $fieldName, $errors )
{
$out = '';
if ( array_key_exists( $fieldName, $errors ) )
{
$out = '<span class="errorMsg">' . $errors[$fieldName] . '</span>';
}
return $out;
}
//------------------------------------------------------------------------
// $errors will be passed to our validate function so we can set error messages per field if desired.
$errors = array();
$formMsg = '';
if ( formWasPosted() )
{
if ( validate( $errors ) )
{
// do processing here
header( 'Location: http://www.example.com/success' );
exit();
}
$formMsg = '<div class="errorNotice">There were problems with your submission</div>';
}
?>
<html><head>
<script type="text/javascript">
function validate()
{
var x=document.forms["Form1"]["comp"].value;
if (x==null || x=="")
{
alert("comp cannot be blank");
return false;
}
}
</script>
<style>
.errorMsg, .errorNotice { color: red; }
.errorNotice { font-size: 150%;}
</style>
</head>
<body>
<?php echo $formMsg; ?>
<form name="Form" action="welcome.php" onsubmit="return validate()" method="post">
<label for="comp">Comp <?php echo getError( 'comp', $errors ); ?></label>
<input id="comp" type="text" name="comp">
</form>
</body>
</html>