Passing variables with data between pages using URL
There are different ways by which values of variables can be passed between pages. One of the ways is to use the URL to pass the values or data. Here the biggest advantage is we can pass data to a different site even running at different servers. Any scripting language like ASP, JSP, PHP or Perl running at receiving end can process and collect the value from the query string or from the URL.
Easy to save the URL or bookmark it for frequent use.
Copy the URL and send it to a friend to refer.
Here one main concern is the data gets exposed in address bar of the browser and can be easily accessible by using browser history. So it is not a good idea to pass sensitive data like password through the URL to different pages or different sites.
Here is an example of passing data through URL within a site.
<a href='page2.php?id=2489&user=tom'>link to page2</a>
When the above link is clicked, page2.php gets the variables id and user with data 2489 and tom respectively. Here is the code to collect data in PHP.
echo $_GET['id']; // output 2489
echo $_GET['user']; // output tom
The address of page2.php can be replaced with any site name and the same data can be passed to another site running in any server. Like this
Passing data outside
<a href=https://www.sitename.com/index.php?id=2489&user=tom>Link to another site</a>
You can see in the above case the values can be posted to another site. Note that after the page name we are using question mark ( ? ) to start the variable data pair and we are separating each variable data pair with one ampersand ( & ) mark.
Submitting form values through GET method
A web form when the method is set to GET method, it submits the values through URL. So we can use one form to generate an URL with variables and data by taking inputs from the users. The form will send the data to a page within the site or outside the site by formatting a query string.
By post method of form submission we can send more number or length of data. Sensitive information like password does not get exposed in URL by POST method, so our login forms we should use POST method to submit data. This is how we collect data submitted by POST method in PHP
Difference between GET and POST
Data remain in Browser History
Data Not available in Browser History
URL with Data can be bookmarked
No data is available in URL to bookmark the page
Data Length Restiction
The restriction (of URL ) is applicable
Can be cached
No meaningful caching
Data like password , pin etc are exposed through URL so they should not be passed using GET method
Better than GET method as data is not exposed through URL
Every scripting language pages has its own way of receiving the data from the URL
While receiving the data based on the server settings the values will be available to the pages. Here in a server running PHP will have to see the global settings of the server on how to collect the data.
Same way in ASP environment running VB script the data can be collected and assigned like this
Id = Request.QueryString("id")
User = Request.QueryString('user')
Passing data within the site using URL
The same principle is used like above to send the data within the site using URL. A query sting can be formatted with a link or a form can be used with get method to pass variables between pages.
Passing the data between the site through URL
Like above data can be passed to different pages of sites using URL . The best use is directly linking to a page dip inside another site by formatting a query sting. Like this
<a href=https://www.sitename.com/viewtopic.php?id=5248>Linking to a topic</a>
Passing variables through query string
In many applications we need to pass variables through query string. For example we want to display the product details where product ID is to be passed in query string through a variable. The product ID can be collected from a table so we don't know what is the value but we can use the variable which stores the product ID.
For example let us say we have collected product id from the product table. Read the tutorial on how to collect data from table. Our link with query string will have something like this.
There is a problem in sending data other than plain text through browser. Empty space and some characters like & if present in the data , will create problem. To maintain the data integrity we have to encode the data before sending them though URL and then decode them again to get back the original data. In PHP encode command is used and in ASP VBScript the command is Server.URLEncode(string)
Security issues while posting data through URL
The most common type of security problem in using data from URL is injection attack.
We must sanitize the date before using inside our script or generating any query to manage database.
how can i pass values with a drop down menu which contains a list of manufacturers name.i want the code to display a value of a variable each time a manufacturer name is selected through the drop down
What PHP code do I use to Post form data to a MYSQL database and at the same time send only some form values to another web page hosted on a different URL.? Thanks!
i can understood the $_POST, but how $_GET works ,
which menthod gets executed when we click on hyperlink?
adi, should be $_GET method.
For example, the url is: xxxxxx/my_prog.php?my_id=1234
Then inside my_prog.php, you can use $_GET[my_id] to get the 1234 like the below
$my_var = $_GET[my_id]
I have 2 separate php environments which I like to have a pass-through of registration and login built. Any help will greatly be appreciated.
create a form with 2 fields that is username and
password then make the server side validation chec if the fields and blank or not,then compare your username and password with server username,password,if equal display on page valid user or display invalid user.
i need to get how to send an ip address value to ip2location text box to evaluate the location n return it
How use a php variable in various page???
how to pass a variable in one page to other using get method but that passing variable should not shown in the url i tried more method i donn't know is it possible if it possible meance pls post
Thank you. =)
i neeed to link first two dropdown boxes and next two dropdown boxes bt they should not be related to each other. . .and also when i perform first one box second box sholud display untill then second box should nt display any info. . plsss help me out