Angular 1.x 下 兼容IE8 placeholder

//用法<input placeholder="" ng-model=''>
.directive('placeholder', function () {
    return {
        restrict: 'A',
        require: '?^ngModel',
        link: function (scope, element, attr) {
            alert(110)
            var scope = scope && scope.$new();
            var validateClass = attr['validateClass'];
            if ('placeholder' in document.createElement('input')) {
                return;
            }
            var _class = element.attr('class');
            var _id = element.attr('id');
            var _style = element.attr('style');
            var elName = element[0].tagName;
            var tip;
            var copyElement, classFlag;
            element.attr('placeholder', '');
            function load() {
                if (elName === 'INPUT') {
                    classFlag = 'copy' + Math.floor(Math.random() * 1000000);
                    element.after("<input class='copy " + classFlag + " " + validateClass + " " + _class + "' id='" + _id + "' style='color:#999;" + _style + "' value='" + tip + "' />");
                    copyElement = $("." + classFlag);
                    scope.init();
                } else if (elName === 'TEXTAREA') {
                    classFlag = 'copy' + Math.floor(Math.random() * 1000000);
                    element.after("<textarea rows=" + attr.rows + " class='copy " + classFlag + " " + _class + "' id='" + _id + "' style='color:#999;" + _style + "' /></textarea>");
                    copyElement = $("." + classFlag);
                    copyElement.val(tip);
                    //指令兼容活动页面,此处select无法监听
                    if (CommonFun.getUrlPara() === 'create') {
                        if (scope.ngModel && (scope.ngModel.type === '单行文本' || scope.ngModel.type === '多行文本')) {
                            element.hide();
                            copyElement.hide();
                        }
                        $('select').change(function () {
                            if ($(this).val() === 0 || $(this).val() === 1) {
                                // element.hide();
                                copyElement.hide();
                            } else {
                                copyElement.show();
                                element.hide();
                                copyElement.focus(function () {
                                    copyElement.hide();
                                    element.show();
                                    element.trigger('focus');
                                });
                                element.blur(function () {
                                    if (element.val() === "") {
                                        copyElement.show();
                                        element.hide();
                                    }
                                });
                            }
                        });
                    } else {
                        scope.init();
                    }
                }
            }

            //指令兼容活动页面
            if (scope.ngModel && scope.ngModel.tip !== undefined && scope.ngModel.tip !== null && scope.ngModel.tip !== '' && CommonFun.getUrlPara() !== 'create') {
                tip = scope.ngModel.tip;
            } else if (scope.ngModel && scope.ngModel.tip === '') {
                tip = '';
            } else {
                attr.$observe('placeholder', function (newV) {
                    tip = newV;
                    load();
                });
            }

            scope.init = function () {
                copyElement.show();
                element.hide();
                //监听input值状态
                scope.$watch(function () { return element.val(); }, function (newV) {
                    if (newV !== null && newV !== undefined && newV.trim() !== "") {
                        copyElement.hide();
                        element.show();
                    } else {
                        copyElement.show();
                        element.hide();
                    }
                });
                copyElement && copyElement.focus(function () {
                    copyElement.hide();
                    element.show();
                    element.trigger('focus');
                });
                element.blur(function () {
                    if (element.val() === "") {
                        copyElement.show();
                        element.hide();
                    }
                });

            };
        }
    };
})