.
.
.
<div id="abschicken">
  <input type="submit" id="sendaway" class="ui-button ui-widget ui-corner-all" value="Abschicken" name="btn[send]">
</div>

var myEl = document.getElementById('sendaway');
myEl.addEventListener('click', function() {

 $(function() {
 
    var createAllErrors = function() {
        var form = $(this);
        var errorList = $('ul.errorMessages', form);
        
        var showAllErrorMessages = function() {
            errorList.empty();
            
            //Find all invalid fields within the form.
            form.find(':invalid').each(function(index, node) {

                //Find the field's corresponding label 
  var label = $('label[for=' + node.id + ']'); 

                //Opera incorrectly does not fill the validationMessage property.
                var message = node.validationMessage || 'Invalid value.';
                errorList
                    .show()
                    .append('<li><span>' + label.html() + '</span> ' + message + '</li>');
            });
        };
        $('input[type=submit], button', form).on('click', showAllErrorMessages);
        $('input[type=text]', form).on('keypress', function(event) { 
   
            //keyCode 13 is Enter
            if (event.keyCode == 13) {
                showAllErrorMessages();
            }
        });  
    }; 
    $('form').each(createAllErrors);
 });
}, false);