What is the correct and the most two common way to start and finish a PHP block of code?
The two most common ways to start and finish a PHP script are:
<?php [ --- PHP code---- ] ?> and <? [--- PHP code ---] ?>
How can we display the output directly to the browser?
To be able to display the output directly to the browser, we have to use the special tags <?= and ?>.
What is the main difference between PHP 4 and PHP 5?
PHP 5 presents many additional OOP (Object Oriented Programming) features.
How To Break A File Path Name Into Parts?
If you have a file name, and want to get different parts of the file name, you can use the pathinfo() function. It breaks the file name into 3 parts: directory name, file base name and file extension; and returns them in an array. Here is a PHP script example on how to use pathinfo():
<?php
$pathName = "/temp/download/todo.txt";
$parts = pathinfo($pathName);
print_r($parts);
print("\n");
?>
This script will print:
Array
(
[dirname] => /temp/download
[basename] => todo.txt
[extension] => txt
)
How To Create A Web Form?
If you take input data from visitors on your Web site, you can create a Web form with input fields to allow visitors to fill in data and submit the data to your server for processing. A Web form can be created with the <FORM> tag with some input tags. The &FORM tag should be written in the following format:
<form action=processing.php method=get/post>
......
</form>
Where "processing.php" specifies the PHP page that processes the submitted data in the form.
What Are Form Input Html Tags?
HTML tags that can be used in a form to collect input data are:
•<SUBMIT ...> - Displayed as a button allow users to submit the form.
•<INPUT TYPE=TEXT ...> - Displayed as an input field to take an input string.
•<INPUT TYPE=RADIO ...> - Displayed as a radio button to take an input flag.
•<INPUT TYPE=CHECKBOX ...> - Displayed as a checkbox button to take an input flag.
•<SELECT ...> - Displayed as a dropdown list to take input selection.
•<TEXTAREA ...> - Displayed as an input area to take a large amount of input text.
How To Generate A Form?
Generating a form seems to be easy. You can use PHP output statements to generate the required <FORM> tag and other input tags. But you should consider to organized your input fields in a table to make your form looks good on the screen. The PHP script below shows you a good example of HTML forms:
<?php
print("<html><form action=processing_forms.php method=post>");
print("<table><tr><td colspan=2>Please enter and submit your"
." comments about PICKZYCenter.com:</td></tr>");
print("<tr><td>Your Name:</td>"
."<td><input type=text name=name></td></tr>\n");
print("<tr><td>Comments:</td>"
."<td><input type=text name=comment></td></tr>\n");
print("<tr><td colspan=2><input type=submit><td></tr></table>\n");
print("</form></html>\n");
?>
If you save this script as a PHP page, submit_comments.php, on your Web site, and view this page, you will see a simple Web form.
Where Is The Submitted Form Data Stored?
When a user submit a form on your Web server, user entered data will be transferred to the PHP engine, which will make the submitted data available to your PHP script for processing in pre-defined arrays:
• $_GET - An associate array that store form data submitted with the GET method.
• $_POST - An associate array that store form data submitted with the POST method.
• $_REQUEST - An associate array that store form data submitted with either GET or POST method. $_REQUEST also contains the cookie values received back from the browser.
The two most common ways to start and finish a PHP script are:
<?php [ --- PHP code---- ] ?> and <? [--- PHP code ---] ?>
How can we display the output directly to the browser?
To be able to display the output directly to the browser, we have to use the special tags <?= and ?>.
What is the main difference between PHP 4 and PHP 5?
PHP 5 presents many additional OOP (Object Oriented Programming) features.
How To Break A File Path Name Into Parts?
If you have a file name, and want to get different parts of the file name, you can use the pathinfo() function. It breaks the file name into 3 parts: directory name, file base name and file extension; and returns them in an array. Here is a PHP script example on how to use pathinfo():
<?php
$pathName = "/temp/download/todo.txt";
$parts = pathinfo($pathName);
print_r($parts);
print("\n");
?>
This script will print:
Array
(
[dirname] => /temp/download
[basename] => todo.txt
[extension] => txt
)
 |
| Naver PHP Most Frequently Asked Latest Interview Questions Answers |
How To Create A Web Form?
If you take input data from visitors on your Web site, you can create a Web form with input fields to allow visitors to fill in data and submit the data to your server for processing. A Web form can be created with the <FORM> tag with some input tags. The &FORM tag should be written in the following format:
<form action=processing.php method=get/post>
......
</form>
Where "processing.php" specifies the PHP page that processes the submitted data in the form.
What Are Form Input Html Tags?
HTML tags that can be used in a form to collect input data are:
•<SUBMIT ...> - Displayed as a button allow users to submit the form.
•<INPUT TYPE=TEXT ...> - Displayed as an input field to take an input string.
•<INPUT TYPE=RADIO ...> - Displayed as a radio button to take an input flag.
•<INPUT TYPE=CHECKBOX ...> - Displayed as a checkbox button to take an input flag.
•<SELECT ...> - Displayed as a dropdown list to take input selection.
•<TEXTAREA ...> - Displayed as an input area to take a large amount of input text.
How To Generate A Form?
Generating a form seems to be easy. You can use PHP output statements to generate the required <FORM> tag and other input tags. But you should consider to organized your input fields in a table to make your form looks good on the screen. The PHP script below shows you a good example of HTML forms:
<?php
print("<html><form action=processing_forms.php method=post>");
print("<table><tr><td colspan=2>Please enter and submit your"
." comments about PICKZYCenter.com:</td></tr>");
print("<tr><td>Your Name:</td>"
."<td><input type=text name=name></td></tr>\n");
print("<tr><td>Comments:</td>"
."<td><input type=text name=comment></td></tr>\n");
print("<tr><td colspan=2><input type=submit><td></tr></table>\n");
print("</form></html>\n");
?>
If you save this script as a PHP page, submit_comments.php, on your Web site, and view this page, you will see a simple Web form.
Where Is The Submitted Form Data Stored?
When a user submit a form on your Web server, user entered data will be transferred to the PHP engine, which will make the submitted data available to your PHP script for processing in pre-defined arrays:
• $_GET - An associate array that store form data submitted with the GET method.
• $_POST - An associate array that store form data submitted with the POST method.
• $_REQUEST - An associate array that store form data submitted with either GET or POST method. $_REQUEST also contains the cookie values received back from the browser.
What is the meaning of a final class and a final method?
'final' is introduced in PHP5. Final class means that this class cannot be extended and a final method cannot be overridden.
How is the comparison of objects done in PHP?
We use the operator '==' to test is two objects are instanced from the same class and have same attributes and equal values. We can test if two objects are referring to the same instance of the same class by the use of the identity operator '==='.
What do the initials of PHP stand for?
PHP means PHP: Hypertext Preprocessor.
Which programming language does PHP resemble?
PHP syntax resembles Perl and C
What does PEAR stand for?
PEAR means "PHP Extension and Application Repository". It extends PHP and provides a higher level of programming for web developers.
What is the actually used PHP version?
Version 7.1 or 7.2 is the recommended version of PHP.
What Happens If An Expected Input Field Was Not Submitted?
Obviously, if an expected input field was not submitted, there will no entry in the $_REQUEST array for that field. You may get an execution error, if you are not checking the existence of the expected entries in $_REQUEST. For example, if you copy processing_forms.php to your local Web server, and run your browser with http://localhost/processing_forms.php?name=Joe, you will an error page like this:
You have submitted the following information:
Name = Joe
Comments =
Thank you!
PHP Notice: Undefined index:
comment in ...\processing_forms.php on line 3
How To Avoid The Undefined Index Error?
If you don't want your PHP page to give out errors as shown in the previous exercise, you should consider checking all expected input fields in $_REQUEST with the isset() function as shown in the example script below:
<?php
if (isset($_REQUEST['name'])) {
$name = $_REQUEST['name'];
} else {
$name = "";
}
if (isset($_REQUEST['comment'])) {
$comment = $_REQUEST['comment'];
} else {
$comment = "";
}
print("<html><pre>");
print("You have submitted the following information:\n");
print(" Name = $name\n");
print(" Comments = $comment\n");
print("Thank you!\n");
print("</pre></html>\n");
?>
How To List All Values Of Submitted Fields?
If you want list all values of submitted fields, you can write a simple loop to retrieve all entries in the $_REQUEST array. Below is an improved version of processing_forms.php to list all submited input values:
<?php
print("<html><pre>");
$count = count($_REQUEST);
print("Number of values: $count\n");
foreach ($_REQUEST as $key=>$value) {
print(" $key = $value\n");
}
print("</pre></html>\n");
?>
How To Retrieve The Original Query String?
If you have coded some values in the URL without using the standard form GET format, you need to retrieve those values in the original query string in $_SERVER['QUERY_STRING']. The script below is an enhanced version of processing_forms.php which print the original query string:
<?php
print("<html><pre>");
print(" query_string = {$_SERVER['QUERY_STRING']}\n");
$count = count($_REQUEST);
print("Number of values: $count\n");
foreach ($_REQUEST as $key=>$value) {
if (is_array($value)) {
print(" $key is an array\n");
for ($i = 0; $i < count($value); $i++) {
$sub_value = $value[$i];
if (get_magic_quotes_gpc()) {
$sub_value = stripslashes($sub_value);
}
print(" ".$key."[".$i."] = ".$sub_value."\n");
}
} else {
if (get_magic_quotes_gpc()) {
$value = stripslashes($value);
}
print(" $key = $value\n");
}
}
print("</pre></html>\n");
?>
How To Support Multiple-page Forms?
If you have a long form with a lots of fields, you may want to divide the fields into multiple groups and present multiple pages with one group of fields on one page. This makes the a long form more user-friendly. However, this requires you to write good scripts that:
• When processing the first page and other middle pages, you must keep those input values collected so far in the session or as hidden values in the next page form.
• When processing the last page, you should collect all input values from all pages for final process, like saving everything to the database.
'final' is introduced in PHP5. Final class means that this class cannot be extended and a final method cannot be overridden.
How is the comparison of objects done in PHP?
We use the operator '==' to test is two objects are instanced from the same class and have same attributes and equal values. We can test if two objects are referring to the same instance of the same class by the use of the identity operator '==='.
What do the initials of PHP stand for?
PHP means PHP: Hypertext Preprocessor.
Which programming language does PHP resemble?
PHP syntax resembles Perl and C
What does PEAR stand for?
PEAR means "PHP Extension and Application Repository". It extends PHP and provides a higher level of programming for web developers.
What is the actually used PHP version?
Version 7.1 or 7.2 is the recommended version of PHP.
What Happens If An Expected Input Field Was Not Submitted?
Obviously, if an expected input field was not submitted, there will no entry in the $_REQUEST array for that field. You may get an execution error, if you are not checking the existence of the expected entries in $_REQUEST. For example, if you copy processing_forms.php to your local Web server, and run your browser with http://localhost/processing_forms.php?name=Joe, you will an error page like this:
You have submitted the following information:
Name = Joe
Comments =
Thank you!
PHP Notice: Undefined index:
comment in ...\processing_forms.php on line 3
How To Avoid The Undefined Index Error?
If you don't want your PHP page to give out errors as shown in the previous exercise, you should consider checking all expected input fields in $_REQUEST with the isset() function as shown in the example script below:
<?php
if (isset($_REQUEST['name'])) {
$name = $_REQUEST['name'];
} else {
$name = "";
}
if (isset($_REQUEST['comment'])) {
$comment = $_REQUEST['comment'];
} else {
$comment = "";
}
print("<html><pre>");
print("You have submitted the following information:\n");
print(" Name = $name\n");
print(" Comments = $comment\n");
print("Thank you!\n");
print("</pre></html>\n");
?>
How To List All Values Of Submitted Fields?
If you want list all values of submitted fields, you can write a simple loop to retrieve all entries in the $_REQUEST array. Below is an improved version of processing_forms.php to list all submited input values:
<?php
print("<html><pre>");
$count = count($_REQUEST);
print("Number of values: $count\n");
foreach ($_REQUEST as $key=>$value) {
print(" $key = $value\n");
}
print("</pre></html>\n");
?>
How To Retrieve The Original Query String?
If you have coded some values in the URL without using the standard form GET format, you need to retrieve those values in the original query string in $_SERVER['QUERY_STRING']. The script below is an enhanced version of processing_forms.php which print the original query string:
<?php
print("<html><pre>");
print(" query_string = {$_SERVER['QUERY_STRING']}\n");
$count = count($_REQUEST);
print("Number of values: $count\n");
foreach ($_REQUEST as $key=>$value) {
if (is_array($value)) {
print(" $key is an array\n");
for ($i = 0; $i < count($value); $i++) {
$sub_value = $value[$i];
if (get_magic_quotes_gpc()) {
$sub_value = stripslashes($sub_value);
}
print(" ".$key."[".$i."] = ".$sub_value."\n");
}
} else {
if (get_magic_quotes_gpc()) {
$value = stripslashes($value);
}
print(" $key = $value\n");
}
}
print("</pre></html>\n");
?>
How To Support Multiple-page Forms?
If you have a long form with a lots of fields, you may want to divide the fields into multiple groups and present multiple pages with one group of fields on one page. This makes the a long form more user-friendly. However, this requires you to write good scripts that:
• When processing the first page and other middle pages, you must keep those input values collected so far in the session or as hidden values in the next page form.
• When processing the last page, you should collect all input values from all pages for final process, like saving everything to the database.