### Replacing form fields by text in PHP

In PHP, the form field has replaced with the custom text after processing by either using an HTML file or hiding the form fields using the PHP script. This method can also be used for applying static header and footer on the web page. In the following example, I have used an HTML file and PHP script to add two numbers. The HTML file content has replaced during the execution.

Before Execution

After Execution

### Source Code:

form.html

<form method="post" action="<?php print $_SERVER['PHP_SELF']; ?>" > First Number: &nbsp;&nbsp;&nbsp;&nbsp;<input type="text" name="first"><br> Second Number: <input type="text" name="second"><br><br> <input type="reset" value="Reset"><input type="submit" value="Submit"> </form> addition.php <html> <head> <title>Adding two numbers</title> </head> <body> <center> <br><br> <h2>Addition of two Numbers</h2> <hr width=40%> <?php if(!$_POST) {
include("form.html");
} else {
$n1 = ($_POST["first"]);
$n2 = ($_POST["second"]);
$n3 =$n1 + $n2; print "<br>Addition of$n1 and $n2 is$n3 <br><br>";
}
?>
<hr width = 40%>
</center>
</body>
</html>

Note: You must save both files in the same directory, and run the PHP file through the webserver.