您的样本中仅有几处修改：
app.directive('placehold', function() {
return {
restrict: 'A',
require: 'ngModel',
link: function(scope, element, attr, ctrl) {
var value;
var placehold = function () {
element.val(attr.placehold)
};
var unplacehold = function () {
element.val('');
};
scope.$watch(attr.ngModel, function (val) {
value = val || '';
});
element.bind('focus', function () {
if(value == '') unplacehold();
});
element.bind('blur', function () {
if (element.val() == '') placehold();
});
ctrl.$formatters.unshift(function (val) {
if (!val) {
placehold();
value = '';
return attr.placehold;
}
return val;
});
}
};
});
您可以在此处进行测试：http ://plnkr.co/edit/8m54JO?p=preview
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