14: Working with Forms in Java

Creating Code39 in Java 14: Working with Forms

The <textarea> element defines the box and its parameters The rows attribute specifies the height of the box in rows based on the font in the text box The cols attribute specifies the width of the box in columns based on the font in the text box The text the user types into the box provides the value, so you need only give the box a name with the name attribute:

<form action= cgi-bin/guestbookcgi action= post > <textarea rows= 10 cols= 30 name= comments > Please include any comments here </textarea> </form>

Any text you include between the <textarea> and </textarea> tags appears in the text box in the browser, as shown in Figure 14-12 The user then enters information in the text box and overrides your text

Submit and reset buttons help the user tell the browser what to do with the form You can create buttons to either submit or reset your form using the <input /> element with the type and value attributes:

Submit Visitors need to tell a browser that they are done with a form and want to send the contents You create a button to submit the form to you by using this markup:

You don t use the name attribute for the submit and reset buttons You use the value attribute instead to specify how the browser labels the buttons for display Reset Visitors need to clear the form if they want to start all over again or decide not to fill it out You create a button to reset, or clear, the form by using the following markup:

You can set the value to anything you want to appear on the button In our example, we set ours to Clear You can use something that s more appropriate to you if you d like Here s an example of markup to create Submit and Reset buttons named Send and Clear, respectively:

<form action= cgi-bin/guestbookcgi action= post > <p>First Name: <input type= text name= firstname size= 30 maxlength= 25 /></p> <p>Last Name: <input type= text name= lastname size= 30 maxlength= 25 /></p> <p>Password: <input type= password name= psswd size= 30 maxlength= 25 /></p> <p>What are some of your favorite foods </p> <p><input type= checkbox name= food value= pizza checked= checked /> Pizza<br /> <input type= checkbox name= food value= icecream />Ice Cream<br /> <input type= checkbox name= food value= eggsham />Green Eggs and Ham<br /> </p> <p>What is your gender </p> <p><input type= radio name= gender value= male />Male<br /> <input type= radio name= gender value= female checked= checked /> Female</p> <p> <input type= submit value= Send /> <input type= reset value= Clear /> </p> </form>

If you don t like the Submit and Reset buttons that a browser creates, you can substitute your own graphical buttons by using The <input /> element with a type of image An src attribute that specifies the image s location A value that defines the result of the field: For an image that submits the form, set value to submit For an image that clears the form, set value to reset Use the alt attribute to provide alternative text for browsers that don t show images (or for users who can t see them) The following markup creates customized submit and reset buttons:

<p><input type= image value= submit src= submit_buttongif alt= Submit /> <input type= image value= reset src= reset_buttongif alt= Clear /> </p>

No matter how brilliant your site s visitors, there s always a chance that they ll enter data you aren t expecting JavaScript to the rescue!

Form validation is the term for checking the data the user enters before it s put into your database Check the data with both JavaScript and Common Gateway Interface (CGI) scripts on your server