Form processing
PHP provides users with many powerful and convenient functions that are convenient and easy to use. In terms of form processing, PHP can automatically assign data sent by the client form to the corresponding variables, thus greatly simplifying the processing process of the entire form.
For example, a user creates the following form:
< INPUT TYPE=TEXT NAME=“name” VALUE=“PETER” >
When using PHP to process the above code, PHP automatically creates a variable named $name and assigns the variable value "PETER" to the variable.
Users can directly perform various operations on variables created by PHP, such as displaying variable values:
echo “Hi $name！”；
Or verify the variable value:
if ($name == “PETER”) { echo “Please check out your email.”； }
Next, let's take a look at how to create and process a basic form by using PHP. In the example, we will ask the form filler to answer several short questions, including entering the form filler’s name, email address, completing the questionnaire, etc.
Here, we divide the page we want to design into two functional modules: form display and form processing according to function. In this way, users do not have to design two different pages, but only need to display or process corresponding functional modules through logical control in the same PHP page. A. Form display
We use the first functional module to display the form. The specific code is:
< ？php
function display_form()
{
global $PHP_SELF;
？ >
< FORM TARGET=“< ？php echo $PHP_SELF; ？ >”METHOD=GET >
Name: < INPUT TYPE=TEXT NAME=“name” >< BR >
Favorite Fruit: < INPUT TYPE=RADIO NAME=“fruit” VALUE=“apple” >Apple
< INPUT TYPE=RADIO NAME=“fruit” VALUE=“orange” >Orange
< INPUT TYPE=RADIO NAME=“fruit” VALUE=“banana” >Banana
Favorite Times to Eat Fruit:
< INPUT TYPE=CHECKBOX NAME=“times[]” VALUE=“m” >Morning
< INPUT TYPE=CHECKBOX NAME=“times[]” VALUE=“n” >Noon
< INPUT TYPE=CHECKBOX NAME=“times[]” VALUE=“d” >Dinner
< INPUT TYPE=CHECKBOX NAME=“times[]” VALUE=“l” >Latenight
< INPUT TYPE=HIDDEN NAME=“stage” VALUE= “results” >
< INPUT TYPE=SUBMIT VALUE= “Thanks!” >
< /FORM >
< ?php
}
? >
Most of the above codes are HTML code necessary to create forms. Here, we will only give a brief introduction to the PHP knowledge involved.
First, let's take a look at the variable $PHP_SELF at the beginning of the code. The variable $PHP_SELF is a very convenient pointer in PHP, and its variable value is the URL address of the current page. In this way, we can achieve the purpose of processing forms by the form page by setting the value of TARGET to $PHP_SELF in the subsequent form tag. Here, we use the $PHP_SELF variable instead of the actual address of the page because by using the $PHP_SELF variable, we can easily modify and move the written page code without worrying about re-entering the new page address after each change.
In addition, when using the $PHP_SELF variable, we adopted the following method:
global $PHP_SELF；
This indicates that the $PHP_SELF variable in the code is a global variable. When using PHP, users must note that any function variables in PHP are local variables. This means that the scope of any function variable is limited to the function itself that includes the variable. Even if there is a variable with the same name outside the function, the value of the variable is also different. Therefore, if we do not explicitly declare the function variable $PHP_SELF as a global variable with a global unique value in the code, the user will find that the value of the variable $PHP_SELF in the function will be empty, rather than the URL address of the current page we expect in advance.
Users may have noticed that we set the name of the form check option to the times[] array and the name of the radio select option to the fruit regular variable. This is because the single-choice option only allows the user to select the only correct option, so the value of the fruit variable may only be a string; on the contrary, the check option allows the user to make multi-choice. If the user wants PHP to save all the choices the user may make, he needs to use an array to save all possible values. According to PHP's syntax rules, we add square brackets to the variable name times to make PHP know that the variable is an array variable rather than a normal regular variable.
Finally, we set an implicit variable called stage, by using this variable, we can control whether the form is displayed or the form results are processed.