jQuery：如何将表单元素上的事件监听器范围扩展到自己的表单？

Question

So I have multiple forms on a page. Each form is identical except for the data they may contain. I am listening for changes to a specific elements that should modify other elements within its same form, but I am having trouble figuring out how to scope those actions within its own form. Here's what I've got so far:

var ContactSponsor = new function(){

    this.init = function(){
        $('#SponsorStatus_ID').change(SponsorStatusChanged);
    };

    var SponsorStatusChanged = function(){

        var $form = $(this).closest('form');
        var selectedValue = $(this).find('option:selected').text();

        if (selectedValue == 'Executed Contract') {
            markFieldRequired('#NumVAPs', $form);
            markFieldRequired('#SponsorWebsiteLevel_ID', $form);
            autoFillFieldWithCurrentDate('#ContractDate', $form);
        } else {
            markFieldNotRequired('#NumVAPs', $form);
            markFieldNotRequired('#SponsorWebsiteLevel_ID', $form);
        }
    };

    var markFieldRequired = function(fieldID, $form){
        $(fieldID, $form).siblings('label').addClass('required');
    };

    var markFieldNotRequired = function(fieldID, $form){
        $(fieldID, $form).siblings('label').removeClass('required');
    };

    var autoFillFieldWithCurrentDate = function(fieldID, $form){
        if ($(fieldID, $form).val() == '' || $(fieldID, $form).val() == '0000-00-00') {
            $(fieldID, $form).val(getCurrentDate());
        }
    };
};

Also, I'm passing the form to each of the methods. Not sure if there is a way I can do this without passing it in every time.

Answer 1

It looks like you're using duplicate IDs. That is probably going to cause problems. Rather than having each FORM include an input with id=NumVAPs , remove the ID and then target the field by name instead eg $form.find('[name=NumVAPs]') .

And hey, while we're at it, you might want to combine your markFieldRequired and markFieldNotRequired functions into a single setFieldRequired that accepts a boolean indicating whether the field should be required or not.

Also, if marking a field as required is purely cosmetic, you may want to consider handling that with some CSS instead. Eg:

var SponsorStatusChanged = function(){
    var $this = $(this);

    if($this.val() == 'Executed Contract') {
        $this.closest('form').addClass('executed');
    }
}

Then, add this CSS:

form.executed label.required-for-executed {
    /* whatever rules are conferred by .required */
}

OR add that selector to the .required block. Also, you'll have to add the class required-for-executed to each of the appropriate labels in the markup (ie don't do it with javascript).