Enforcing the maxlength attribute on mobile browsers
Try this one:
var $input = $('input')$input.keyup(function(e) { var max = 5; if ($input.val().length > max) { $input.val($input.val().substr(0, max)); }});jsFiddle here: http://jsfiddle.net/fttk2/1/
var max = 1input.addEventListener('keyup', function (event) { event.target.value = event.target.value.substring(0, max)})
This problem is because predictive text is enabled on your keyboard, disable it and try again