That .toggle()
method was removed from jQuery in version 1.9. You can do this instead:
$(document).ready(function() {
$('#showmenu').click(function() {
$('.menu').slideToggle("fast");
});
});
Demo: http://jsfiddle.net/APA2S/1/
…but as with the code in your question that would slide up or down. To slide left or right you can do the following:
$(document).ready(function() {
$('#showmenu').click(function() {
$('.menu').toggle("slide");
});
});
Demo: http://jsfiddle.net/APA2S/2/
Noting that this requires jQuery-UI’s slide effect, but you added that tag to your question so I assume that is OK.