The file_put_contents ( ) function is used to Append to a file.
Syntax:
file_put_contents(file,data,mode,context)
Example:
< ?php
＄txt = "Student id ";
＄myfile = file_put_contents('logs.txt', $txt.
PHP_EOL , FILE_APPEND | LOCK_EX);
? >

PHP Close a File:
The fclose ( ) function is used to close an opened file.
The file object comes from fopen function.
Syntax:
fclose($file_Object);
Example:
< ?php
＄myfile = fopen("student.txt", "r'');
/ / some code to be executed ....
fclose( ＄myfiIe);
? >

PHP Read a File:
The fread ( ) function reads from an open file.
The file object comes from fopen function.
Syntax:
fread(＄file_Object,filesize("FileName''));
Example:
< ?php
fread (＄myfiIe,filesize("Student. txt''));
? >

Validation rules for HTML input field:

< html >
< head >
< title > Login Form < /title >
< body >
< h3 align=center > TamiiNadu State Council of
EducationalResearchand Training, Chennai < /h3 >
< Form Action = "mailto:abcd.xyz@com"
method =post >
< p > User Name:
OUTPUT:
< Input type = text name="user_name" size = 20 maxlength = 15 > < /p >
< p > Password:
< Input type = password name="pass" size = 20 maxlength = 15 > < /p >
< Input type = reset value = "Clear" >
< Input type = submit value = "Login" >
< /Form >
< /body >
< /html >