(i) fopen( ) is a system function available in PHP.
(ii) This function helps to open a file in the server.
(iii) It contains two parameters one for the file and the other one specifies in which mode the file should be opened (Read / Write)

After the submission of data, validations are performed on the server side using the programming like PHP, ASP or JSP etc. available in the server machine.

The input data validations are performed on the client machine's web browsers using client side scripts like Java script or adding "required" attribute in HTML input tags.

Asynchronous JavaScript And XML.

This attribute is used to specify, how the browser encodes the data before it sends it to the server.

Syntax:
\($\)file_Object = fopen("FileName", "Read/WriteMode") or die("Error Message!");

Syntax:
< input type="file" name="myFile" >

The browser button defined a file-select filed and a "Browse" button for file uploads.

File handling is an important activity of all web application development process.

Syntax:
<Input type = "text" name = "name">

The following control are available in HTML forms:
(i) Text inputs
(ii) Buttons
(iii) Checkbox
(iv) Radio box
(v) File Select
(vi) Form Tag

Validation is a process of checking the input data submitted by the user from client machine.

(i) Form tag is used to mention a method (POST or GET) and control the entire form controls in the HTML document.
(ii) All input values are synchronized and sent to the server via POST or GET method.

HTML form controls are used to collect data from user.