Cross browser input event observer

Use it as global variable:

var x = new XInput();
x.observe(elInput);
x.oninput = function(){
    console.log('input changed');
};

Or use it as amd module:

require(['./XInput'], function(XInput){
    var x = new XInput();
    x.observe(elInput);
    x.oninput = function(){
        console.log('input changed');
    };
});

• observe: start observing the change
• neglect: stop observing the change
• sync: sync up input value (usually after value is changed by code)
• trigger: will call into oninput event handler

• oninput: will be called once the input value gets changed