Hi guys.
I have a small problem understanding a very small part of the below code (an Interactive Form built using PHP).
if ( isset( $_POST[“submitButton”] ) ) {
processForm();
} else {
displayForm( array() );
}
function validateField( $fieldName, $missingFields ) {
if ( in_array( $fieldName, $missingFields ) ) {
echo ‘ class=”error”’;
}
}
function setValue( $fieldName ) {
if ( isset( $_POST[$fieldName] ) ) {
echo $_POST[$fieldName];
}
}
function setChecked( $fieldName, $fieldValue ) {
if ( isset( $_POST[$fieldName] ) and $_POST[$fieldName] == $fieldValue ) {
echo ‘ checked=”checked”’;
}
}
function setSelected( $fieldName, $fieldValue ) {
if ( isset( $_POST[$fieldName] ) and $_POST[$fieldName] == $fieldValue ) {
echo ‘ selected=”selected”’;
}
}
function processForm() {
$requiredFields = array( “firstName”, “lastName”, “password1”,
“password2”, “gender” );
$missingFields = array();
foreach ( $requiredFields as $requiredField ) {
if ( !isset( $_POST[$requiredField] ) or !$_POST[$requiredField] ) {
$missingFields[] = $requiredField;
}
}
if ( $missingFields ) {
displayForm( $missingFields );
} else {
displayThanks();
}
}
function displayForm( $missingFields ) {
?>
<h1>Membership Form</h1>
<?php if ( $missingFields ) { ?>
<p class=”error”>There were some problems with the form you submitted.
Please complete the fields highlighted below and click Send Details to
resend the form.</p>
<?php } else { ?>
<p>Thanks for choosing to join The Widget Club. To register, please
fill in your details below and click Send Details. Fields marked with an
asterisk (*) are required.</p>
<?php } ?>
<form action=”registration.php” method=”post”>
<div style=”width: 30em;”>
<label for=”firstName”<?php validateField( “firstName”,
$missingFields ) ?>>First name *</label>
<input type=”text” name=”firstName” id=”firstName”
value=”<?php setValue( “firstName” ) ?>” />
<label for=”lastName”<?php validateField( “lastName”,
$missingFields ) ?>>Last name *</label>
<input type=”text” name=”lastName” id=”lastName” value=
”<?php setValue( “lastName” ) ?>” />
<label for=”password1”<?php if ( $missingFields ) echo
‘ class=”error”’ ?>>Choose a password *</label>
<input type=”password” name=”password1” id=”password1” value=”” />
<label for=”password2”<?php if ( $missingFields ) echo
‘ class=”error”’ ?>>Retype password *</label>
<input type=”password” name=”password2” id=”password2” value=”” />
<label<?php validateField( “gender”, $missingFields ) ?>>Your
gender: *</label>
<label for=”genderMale”>Male</label>
<input type=”radio” name=”gender” id=”genderMale” value=
”M”<?php setChecked( “gender”, “M” )?>/>
<label for=”genderFemale”>Female</label>
<input type=”radio” name=”gender” id=”genderFemale” value=
”F”<?php setChecked( “gender”, “F” )?> />
<label for=”favoriteWidget”>What’s your favorite widget? *</label>
<select name=”favoriteWidget” id=”favoriteWidget” size=”1”>
<option value=”superWidget”<?php setSelected( “favoriteWidget”,
“superWidget” ) ?>>The SuperWidget</option>
<option value=”megaWidget”<?php setSelected( “favoriteWidget”,
“megaWidget” ) ?>>The MegaWidget</option>
<option value=”wonderWidget”<?php setSelected( “favoriteWidget”,
“wonderWidget” ) ?>>The WonderWidget</option>
</select>
<label for=”newsletter”>Do you want to receive our newsletter?
</label>
<input type=”checkbox” name=”newsletter” id=”newsletter” value=”yes”
<?php setChecked( “newsletter”, “yes” ) ?> />
<label for=”comments”>Any comments?</label>
<textarea name=”comments” id=”comments” rows=”4” cols=”50”><?php
setValue( “comments” ) ?></textarea>
<div style=”clear: both;”>
<input type=”submit” name=”submitButton” id=”submitButton” value=
”Send Details” />
<input type=”reset” name=”resetButton” id=”resetButton”
value=”Reset Form” style=”margin-right: 20px;” />
</div>
</div>
</form>
<?php
}
function displayThanks() {
?>
<h1>Thank You</h1>
<p>Thank you, your application has been received.</p>
<?php
}
............ The only problem I am having understanding the above code is the below function:
function processForm() {
$requiredFields = array( “firstName”, “lastName”, “password1”,
“password2”, “gender” );
$missingFields = array();
foreach ( $requiredFields as $requiredField ) {
if ( !isset( $_POST[$requiredField] ) or !$_POST[$requiredField] ) {
$missingFields[] = $requiredField;
}
}
if ( $missingFields ) {
displayForm( $missingFields );
} else {
displayThanks();
}
}
...... to be more specific, this line:
if ( !isset( $_POST[$requiredField] ) or !$_POST[$requiredField] ) {
... In the book I am reading, it states the following about the above function:
Now the function loops through the required field names and looks for each field name in the $POST
array. If the field name doesn ’ t exist, or if it does exist but its value is empty, the field name is added to
the $missingFields array:
foreach ( $requiredFields as $requiredField ) {
if ( !isset( $POST[$requiredField] ) or !$_POST[$requiredField] ) {
$missingFields[] = $requiredField;
}
}
..... now, to me, when I look at the below line:
if ( !isset( $_POST[$requiredField] ) or !$_POST[$requiredField] ) {
........ this snippet of the if statement:
!isset( $_POST[$requiredField] )
... looks like it is doing the exact same thing as the next snippet:
or !$_POST[$requiredField]
They both look like they are checking whether the variable: $requiredField holds a value.
How is it that the first snippet checks whether the form field exists and the second part checks whether that form field holds a value?
Because to me:
or !$_POST[$requiredField]
.... looks like it is merely checking whether $requiredFiled is holding one of the values in the array.
Paul.
