表单验证无法在jQuery中使用

Question

I'm trying a form validation in jQuery but it's not working the way I'm doing it. I want the border of the input to turn red if the input area is empty when I focus out.

OR

I want to add the bootstrap class called "has-danger", which turns the border and the background red-ish, if the input area is empty.

Here's the code:

<fieldset class="form-group"> <br>
    <label for="name">Name</label> <br><br>
    <input type="name" class="form-control" id="name"> <br>
</fieldset>

jQuery code 1:

$("#name").blur(function() {
    if((this).val() == "" ) {
        $(this).addClass("has-danger");
    }
});

jQuery code 2:

$("#name").blur(function() {
    if((this).val() == "" ) {
        $(this).css("border", "solid 1px red");
    }

Answer 1

you are missing the $ just before (this) in your if statement

Note: I've added an else for when the field is filled the border gets removed

 $("#name").blur(function() { if ($(this).val() == "") { $(this).css("border", "solid 1px red"); } else { $(this).css("border", ""); } }); 

 <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script> <fieldset class="form-group"> <label for="name">Name</label> <input type="name" class="form-control" id="name"> </fieldset>