PHP form-3 (PHP form-required field)

Phpform-Required fields

This section describes how to set required fields and error messages for a form.

PHP-Required Fields

In the previous section we have introduced the table validation rules, we can see "First name", "E-mail", and "gender" fields are required, each field cannot be empty.

Field	validation rules
Name	Necessary. + can contain only letters and spaces
E-Mail	Necessary. + must contain a valid e-mail address (contains "@" and ".") ）
Url	Optional. If it exists, it must contain a valid URL
Note	Optional. Multi-line field (text field).
Gender	Necessary. One must be selected.

If in the previous section, all input fields are optional.

In the following code we have added some new variables: $NAMEERR, $EMAILERR, $GENDERERR, and $WEBSITEERR. These error variables are displayed on the required fields. We also added an if Else statement for each $_post variable. These statements will check if the $_post variable is empty (using PHP's Empty () function). If blank, the corresponding error message is displayed. If not NULL, the data is passed to the Test_input () function:

<?PHP//define a variable and set it to a null value by default$NAMEERR=$EMAILERR=$GENDERERR=$WEBSITEERR= "";$name=$email=$gender=$comment=$website= "";if($_server["request_method"] = = "POST") {  if(Empty($_post["Name"])) {    $NAMEERR= "Name is required." "; } Else {    $name= Test_input ($_post["Name"]); }  if(Empty($_post["Email"])) {    $EMAILERR= "Mailbox is required. "; } Else {    $email= Test_input ($_post["Email"]); }  if(Empty($_post["Website"])) {    $website= ""; } Else {    $website= Test_input ($_post["Website"]); }  if(Empty($_post["Comment"])) {    $comment= ""; } Else {    $comment= Test_input ($_post["Comment"]); }  if(Empty($_post["Gender"])) {    $GENDERERR= "Gender is required." "; } Else {    $gender= Test_input ($_post["Gender"]); }}?>

PHP-Displaying error messages

In the following HTML instance form, we have added some scripts for each field, and each script displays an error message when the information is entered incorrectly. (If the user submits the form without filling in the information, it will output an error message):

<form method= "POST" action= "<?php Echo htmlspecialchars ($_server[' php_self ']);? > ">name: <input type= "text" name= "name" > <spanclass= "Error" >* <?phpEcho $NAMEERR;? ></span> <br><br>E-Mail: <input type= "text" name= "email" > <spanclass= "Error" >* <?phpEcho $EMAILERR;? ></span> <br><br>website: <input type= "text" name= "website" > <spanclass= "Error" ><?phpEcho $WEBSITEERR;? ></span> <br><br>Notes: <textarea name= "comment" rows= "5" cols= "></textarea>" <br><br>Sex: <input type= "Radio" name= "Gender" value= "female" >female<input type= "Radio" name= "Gender" value= "male" >male<spanclass= "Error" >* <?phpEcho $GENDERERR;? ></span> <br><br> <input type= "Submit" name= "submit" value= "Submit" > </form>

PHP form-3 (PHP form-required field)