class method Form.Element.present
Form.Element.present(element) → Element
Returns true
if a text input has contents, false
otherwise.
Example
This method is very handy in a generic form validation routine. On the following form's submit event, the presence of each text input is checked and lets the user know if they left a text input blank.
<form id="example" class="example" action="#">
<fieldset>
<legend>User Details</legend>
<p id="msg" class="message">Please fill out the following fields:</p>
<p>
<label for="username">Username</label>
<input id="username" type="text" name="username" />
</p>
<p>
<label for="email">Email Address</label>
<input id="email" type="text" name="email" />
</p>
<input type="submit" value="submit" />
</fieldset>
</form>
<script type="text/javascript">
$('example').onsubmit = function(){
var valid, msg = $('msg')
// are both fields present?
valid = $(this.username).present() && $(this.email).present()
if (valid) {
// in the 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('Please fill out <em>all</em> the fields.').style.color = 'red'
}
return false
}
</script>
This method can be called either as an instance method or as a generic method. If calling as a generic, pass the instance in as the first argument.