| Radio Button Input Validation | |
| Radio buttons allow for the direct input of a restricted amount of input. Validating if a value was selected prior to the client sending null input to your application can save a lot of server-side validation. The following example has four possible selections. When the submit button is clicked and none of the radio buttons have been selected an alert box will appear instructing the person to make a selection prior to submission. A simple loop is constructed to check each radio button selection for a value of true or false. If a selection has been made it will pass a value of true. | |
| <html> <title>Radio Button Validation</title> <body bgcolor="#FFFFFF"> <script language="JavaScript"> <!-- function radio_button_checker() { // set var radio_choice to false var radio_choice = false; // Loop from zero to the one minus the number of radio button selections for (counter = 0; counter < radio_form.radio_button.length; counter++) { // If a radio button has been selected it will return true // (If not it will return false) if (radio_form.radio_button[counter].checked) radio_choice = true; } if (!radio_choice) { // If there were no selections made display an alert box alert("Please select a letter.") return (false); } return (true); } --> </script> <form method="get" action="http://www.codeave.com/html/get.asp" onsubmit="return radio_button_checker()" name="radio_form"> <input type="radio" value="A" name="radio_button">A <br> <input type="radio" value="B" name="radio_button">B <br> <input type="radio" value="C" name="radio_button">C <br> <input type="radio" value="D" name="radio_button">D <br> <input type="submit" value="Submit"> </form> </body> </html> |
Monday, December 05, 2011
Radio Button Input Validation
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