Part II: Using JavaScript to Enhance Your Pages in Java
Part II: Using JavaScript to Enhance Your Pages Draw QR Code JIS X 0510 In Java Using Barcode generation for Java Control to generate, create QR Code image in Java applications. 6 Check to see if the current element has been selected Here currentOption is an object, and it has a selected property This property tells you if the object has been highlighted by the user selected is a Boolean property, so the only possible values are true or false if (currentOptionselected == true){ 7 If the element has been selected, add an entry to the output list If the user has highlighted this object, create an entry in the unordered list housed in the result variable: Barcode Generation In Java Using Barcode encoder for Java Control to generate, create barcode image in Java applications. result += <li> + currentOptionvalue + <\/li> \n ; Recognize Bar Code In Java Using Barcode recognizer for Java Control to read, scan read, scan image in Java applications. 8 Close up the list When the loop has finished cycling through all the objects, you can close up the unordered list you ve been building: result += <\/ul> \n ; 9 Print results to the output div The innerHTML property of the output div is a perfect place to print out the unordered list: output = documentgetElementById( output ); outputinnerHTML = result; There s something strange going on here The options of a select box act like an array An unordered list is a lot like an array, which is a lot like a select box Bingo! They are arrays, just in different forms Any listed data can be thought of as an array Sometimes you organize it like a list (for display), sometimes like an array (for storage in memory,) and sometimes it s a select group (for user input) Now you re starting to think like a programmer! Paint QR In C# Using Barcode generator for .NET framework Control to generate, create QR-Code image in Visual Studio .NET applications. Check, Please Reading Check Boxes
QR Code Printer In .NET Framework Using Barcode maker for .NET Control to generate, create QR Code ISO/IEC18004 image in .NET applications. Check boxes fulfill another useful data-input function: They re useful any time you have Boolean data If some value can be true or false, a check box is a good tool Figure 7-3 illustrates a page responding to check boxes It s important to understand that check boxes are independent of each other Although they are often found in groups, any check box can be checked or unchecked regardless of the status of its neighbors QR Generator In Visual Basic .NET Using Barcode encoder for .NET Control to generate, create QR Code ISO/IEC18004 image in .NET applications. 7: Getting Valid Input
EAN128 Creation In Java Using Barcode maker for Java Control to generate, create EAN 128 image in Java applications. Select as many boxes as you want Order Pizza button
Bar Code Creation In Java Using Barcode creator for Java Control to generate, create bar code image in Java applications. Figure 7-3: You can pick your toppings here Choose as many as you like
Paint Code-128 In Java Using Barcode creation for Java Control to generate, create Code 128 Code Set B image in Java applications. When you click the Order Pizza button, the selected output displays here
Bar Code Creation In Java Using Barcode generation for Java Control to generate, create bar code image in Java applications. Building the checkbox page
Encode European Article Number 13 In Java Using Barcode drawer for Java Control to generate, create GS1 - 13 image in Java applications. As usual, start by looking at the HTML: <body> <h1>What do you want on your pizza </h1> <form action = > <fieldset> <input type = checkbox id = chkPepperoni value = pepperoni /> <label for = chkPepperoni >Pepperoni</label> <input type = checkbox id = chkMushroom value = mushrooms /> <label for = chkMushroom >Mushrooms</label> Encoding RM4SCC In Java Using Barcode printer for Java Control to generate, create RoyalMail4SCC image in Java applications. Part II: Using JavaScript to Enhance Your Pages
Barcode Drawer In Visual C# Using Barcode maker for .NET framework Control to generate, create barcode image in VS .NET applications. <input type = checkbox id = chkSausage value = sausage /> <label for = chkSausage >Sausage</label> <button type = button onclick = order() > Order Pizza </button> </fieldset> </form> <h2>Your order:</h2> <div id = output > </div> </body> Each check box is an individual input element Note that checkbox values are not displayed Instead, a label (or similar text) is usually placed after the check box A button calls an order() function Look at the labels They each have the for attribute set to tie the label to the corresponding check box Although this is not required, it s a nice touch, because then the user can click the entire label to activate the check box Printing Data Matrix 2d Barcode In Visual C#.NET Using Barcode maker for .NET Control to generate, create Data Matrix image in .NET framework applications. Responding to the check boxes
UPCA Recognizer In .NET Using Barcode scanner for .NET Control to read, scan read, scan image in Visual Studio .NET applications. Check boxes don t require a lot of care and feeding When you extract a checkbox object, it has two critical properties: The value property: Like other input elements, the value property can be used to store a value associated with the check box The checked property: This property is a Boolean value, indicating whether the check box is currently checked The code for the order() function shows how it s done: <script type = text/javascript > //<![CDATA[ //from checkBoxeshtml function order(){ //get variables var chkPepperoni = document getElementById( chkPepperoni ); var chkMushroom = document getElementById( chkMushroom ); var chkSausage = document getElementById( chkSausage ); Printing Barcode In .NET Framework Using Barcode encoder for ASP.NET Control to generate, create bar code image in ASP.NET applications. 7: Getting Valid Input
Code 128C Scanner In VS .NET Using Barcode recognizer for .NET Control to read, scan read, scan image in VS .NET applications. var output = documentgetElementById( output ); var result = <ul> \n if (chkPepperonichecked){ result += <li> + chkPepperonivalue + <\/li> \n ; } // end if if (chkMushroomchecked){ result += <li> + chkMushroomvalue + <\/li> \n ; } // end if if (chkSausagechecked){ result += <li> + chkSausagevalue + <\/li> \n ; } // end if result += <\/ul> \n outputinnerHTML = result; } // end function //]]> </script> For each check box, make sure you use both of its properties: 1 Determine whether the check box is checked Use the checked property as a condition 2 If the box is checked, return the value property associated with the check box Often in practice the value property is left out The important thing is whether the check box is checked It s pretty obvious that if chkMushroom is checked, the user wants mushrooms, so you may not need to explicitly store that data in the checkbox itself Encoding Bar Code In .NET Using Barcode creator for Visual Studio .NET Control to generate, create barcode image in .NET framework applications. GTIN - 13 Reader In Visual Studio .NET Using Barcode scanner for .NET Control to read, scan read, scan image in .NET applications. |
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