- Prototype Tutorial
- Prototype - Home
- Prototype - Short Overview
- Prototype - Useful Features
- Prototype - Utility Methods
- Prototype - Element Object
- Prototype - Number Processing
- Prototype - Strings Processing
- Prototype - Array Processing
- Prototype - Hash processing
- Prototype - Basic Object
- Prototype - Templating
- Prototype - Enumerating
- Prototype - Event Handling
- Prototype - Form Management
- Prototype - JSON Support
- Prototype - AJAX Support
- Prototype - Expressing Ranges
- Prototype - Periodical Execution
- Prototype Useful Resources
- Prototype - Quick Guide
- Prototype - Useful Resources
- Prototype - Discussion
Prototype - Form.Element present() Method
This method returns true if a text input has contents, false otherwise.
Syntax
formElement.present();
Return Value
It returns true if a text input has contents, false otherwise.
Example
Try to submit the following form first without filling out the information, then again after typing some text in the fields −
<html> <head> <title>Prototype examples</title> <script type = "text/javascript" src = "/javascript/prototype.js"></script> <script> function showResult() { var valid, msg = $('msg') // are both fields present? valid = $('username').present() && $('email').present() if (valid) { // in real world we would return true here to allow the // form to be submitted return true msg.update('Passed validation!').style.color = 'green' } else { msg.update('Fill out all the fields.').style.color = 'red' } return false } </script> </head> <body> <p>Click the button to see the result.</p> <br /> <form id = "example" action = "#"> <fieldset> <legend>User Details</legend> <p style = "color:green;" id = "msg"> Fill out all the fields: </p> <div> <label for = "username">Username</label> <input id = "username" name = "username" type = "text"> </div> <div> <label for = "email">Email Address</label> <input id = "email" name = "email" type = "text"> </div> <div> <input value = "result" type = "button" onclick = "showResult()";> </div> </fieldset> </form> </body> </html>
Output
prototype_form_management.htm
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