Page 285 - Beginning PHP 5.3

Chapter 9: Handling HTML Forms with PHP
Next the script defines some helper functions. validateField() is used within the form to display a
red error box around a form field label if the required field hasn’t been filled in. It’s passed a field
name, and a list of all the required fields that weren’t filled in. If the field name is within the list, it
displays the markup for the error box:

function validateField( $fieldName, $missingFields ) {
if ( in_array( $fieldName, $missingFields ) ) {
echo “ class=”error”;’;
}
}

setValue() is used to prefill the text input fields and text area field in the form. It expects to be passed a
field name. It then looks up the field name in the $_POST superglobal array and, if found, it outputs the
field ’ s value:

function setValue( $fieldName ) {
if ( isset( $_POST[$fieldName] ) ) {
echo $_POST[$fieldName];
}

}
setChecked() is used to preselect checkboxes and radio buttons by inserting a checked attribute into
the element tag. Similarly, setSelected() is used to preselect an option in a select list via the
selected attribute. Both functions look for the supplied field name in the $_POST array and, if the field
is found and its value matches the supplied field value, the control is preselected:

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”’;
}
}

Next comes the form handling function, processForm() . This sets up an array of required field names,
and also initializes an array to hold the required fields that weren ’ t filled in:
function processForm() {
$requiredFields = array( “firstName”, “lastName”, “password1”, “password2”,
“gender” );
$missingFields = array();

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