Defining Form Parameters in Java

Paint QR Code 2d barcode in Java Defining Form Parameters

The whole point of dynamic Web pages is to not return the same page each time a page is requested One tool that s used to mix up what s returned is a form parameter When you add a form to your page (as described in Book II, 7), you need to keep track of how you submit your form data to the server You have two methods to choose from: The POST method, which sends parameters in the body of the request The GET method, which places the data in the URL as parameters

You can use either GET or POST methods, but you need to be consistent about which you use between the page that submits the values and the page that processes them You need the type of request when you tell Dreamweaver about your form input You also need to know the field names listed in the Field Properties dialog box because you need to create a form parameter for each of these fields To view the field name, select the form field with the Properties inspector open To add a data source for a form field, follow these steps:

Window Bindings Before you create any bindings, you see the Dynamic Page setup checklist in the Bindings panel

appropriate form item for your dynamic page type Options appear on the list based on your dynamic page type Table 1-1 lists the option names to select for each page type

Table 1-1

The Form Variable dialog box displays, as shown in Figure 1-3

The form parameter name is normally the name of the HTML form field or object that the parameter uses to obtain its value For example, if the field on your form is labeled Username, enter username in the dialog box The form parameter appears in the Bindings panel, as shown in Figure 1-4

After you define the form parameter as a data source, you can insert the parameter in your document by selecting it in the Bindings panel See Book VIII, 3 for details

URL parameters are a simple way of passing information to the Web server as part of the Web page request When the Web server receives the request, the URL parameter is included in that request This allows dynamic pages to be generated based on a specific parameter from a prior page In the URL, a question mark ( ) separates the Web site location from the parameters Here s an example:

In this example, the Web site is http://wwwexamplecom The two parameters are username (which has a value of jon) and password (which has a value of test) An equal sign (=) separates each parameter from its value If more than one parameter exists, as in this example, an ampersand (&) separates the parameters Passing these values to the server is important because it allows the server to determine if the username and password are valid Username and password validity determines access to subsequent pages

When a server processes a Web page request that contains URL parameters, the server makes those parameter values available to the dynamic page before returning the page to the Web browser, where the user sees the updated page displayed Dreamweaver uses URL parameters automatically when you submit a form by using the HTTP GET method The GET method specifies that the parameters are appended to the URL when the page request is sent to the Web server URL parameters are also frequently used to pass a value to the Web server, such as an action to take, when the user clicks a link For example, you may have a URL parameter called action that takes the values insert, update, and delete based on the action that the link indicates You can pass more than one URL parameter at a time to a Web site To define a data source binding for a URL parameter, follow these steps:

1 Create a new dynamic page or open an existing dynamic page 2 If you don t already have the Bindings panel displayed, choose

Window Bindings Before you create any bindings, you see the Dynamic Page setup checklist in the Bindings panel