vue.js focus net directive

    Vue.directive('focusNext', {
        bind: function () {
            this.handler = function () {
                if (this.el.value.length >= this.expression) {
                    var next = this.el.nextSibling;
                    next.focus();
                }
            }.bind(this)
            this.el.addEventListener('input', this.handler)
        },
        unbind: function () {
            this.el.removeEventListener('input', this.handler)
        }
    })
    var vm = new Vue({
        el: '# demo',
    })

关键字：vue.js, vue, directive, focus