Problems with jQuery Validate on Select List

问题

I've seen tons of samples of how to use jQuery Validation on a select list - and I'm attempting to implement one, but it just isn't functioning for me. I'm really new to the plugin in general and am just completely baffled about what I am doing wrong.

The intended behavior is that it should not validate if the user has left the select menu on "default". They have to make a selection.

I start by wiring up the new validator method.

Javascript

(function($) {
    $.validator.addMethod('mustbe', function(value, element, params) {
        var testValue = params['propertyvalue'];
        var condition = params['condition'];
        if ((condition == '0') && (value != testValue)) return true;
        if ((condition == '1') && (value == testValue)) return true;
        return false;
    });
})(jQuery);

$(document).ready(function() {
    $("#form1").validate();

    $('#form1').submit(function() {
        alert($('#form1').valid());
    });
});​

Then I followup by adding the metadata to the actual HTML.

HTML

<form id="form1" action="">
<select id="select_list" data-val="true"
        data-val-mustbe="You must select a value"
        data-val-mustbe-condition="0"
        data-val-mustbe-propertyvalue="default"
        data-val-required="You must select a value" >
        <option value="default">Choose...</option>
        <option value="1">1</option>
        <option value="2">2</option>
</select>
<input type="submit" id="submit" value="Submit" />
</form>​

And it just refuses to validate. Here is a link to a fiddle, too :

jsFiddle

回答1:

You should have told you are using ASP.NET MVC. It wouldn't help but people would stop asking about custom attribute names.

I have redesigned your code to work with value default and your data-val attributes. This is a code sample:

$(document).ready(function() {    
    $.validator.addMethod("valueNotEquals", function(value, element, arg){
        return arg != value;
    }, "");

    $("#form1").validate({
        rules: {
            select_list : {valueNotEquals: $('#select_list').attr('data-val-mustbe-propertyvalue')},  
        },
        messages: {  
            select_list : { valueNotEquals: $('#select_list').attr('data-val-required') }
        },        
        submitHandler: function(form) {
            alert($('#form1').valid());
            form.submit();
        }
    });
});

EDIT :

And here's a jsFiddle example: http://jsfiddle.net/Gajotres/ekPpS/

And here's a version without ASP.NET MVC attributes:

<form id="form1" action="">
    <select id="select_list" name="select_list">
            <option value="default">Choose...</option>
            <option value="1">1</option>
            <option value="2">2</option>
    </select>
    <input type="submit" id="submit" value="Submit" />
</form>

$(document).ready(function() {    
    $.validator.addMethod("valueNotEquals", function(value, element, arg){
        return arg != value;
    }, "");

    $("#form1").validate({
        rules: {
            select_list : {valueNotEquals: "default"},  
        },
        messages: {  
            select_list : { valueNotEquals: "You must select a value" }
        },        
        submitHandler: function(form) {
            alert($('#form1').valid());
            form.submit();
        }
    });
});

回答2:

The simple way is to use value='' in the default option, and specify that the select is required:

<select id="select_list" class="required">

回答3:

So the answer by Barmar is partially correct but not well explained.

changes I made to get this updated fiddle to work:

added name="select_list" to the select element itself to give jquery.validate what it wants to look for

modified the javascript validate call:

$("#form1").validate({
  rules: {
    select_list: {
      required: true,
      number: true
    }
  },
 submitHandler: function(form) {
   alert($('#form1').valid());
   form.submit();
 }
});

来源：https://stackoverflow.com/questions/14078482/problems-with-jquery-validate-on-select-list