Disable button based on attribute in javascript

Question

I have a form which processes data and puts it in to a csv. A user can add multiple rows to the form to add a new item. To make this a unique item the id is incremented by 1 (ex. item[0] goes to item1)

The form works great but I am trying to add a delete / remove button. It works except I don't want it to remove the very last item.

Below is the code I am using. I am having trouble as this if statement breaks the add crew button.

    $('#btnDelelte').click(function () {
        //remove the last form item
        $('.questions:last-child').remove();

        // if only element that remains as ID == 0, disable the "remove" button
        if ($('.questions:last-child').attr('id' == 0) 
            $('#btnDelelte').attr('disabled', 'disabled');

    });

If you comment out the if statement, and run the jsfiddle all the buttons work but you are able to delete the last form area.

jsfiddle

Answer 1

在控制台中它说:

Uncaught SyntaxError:意外的标识符

查看错误的位置,您可以看到属性方法未正确关闭.

if ($('.questions:last-child').attr('id' == 0)  

它应该是

if ($('.questions:last-child').attr('id') == 0) 
                                        ^