如何找到一个类的所有子元素并检查是否为空？

Question

I have a form and need to check to make sure any child inputs of a fieldset are empty. How can I accomplish this using jQuery?

if any fields with .required are empty -> there are fields that have not been filled out if all fields with .required have been filed out -> they have all been filed out

Answer 1

Select your fields by form id and class name. Then use .filter() to reduce your set to include only the fields that have not been filled out:

var emptyFields = $("#myForm .required").filter(function()
{
    return $(this).val() == "";
});

If you don't want to do anything with the fields, but just need a boolean:

var anyEmptyFields = !!emptyFields.length;

Answer 2

尝试这个：

var emptyRequiredFields = jQuery("#post-form .required:input").not("[value]");

Answer 3

Try this:

    <fieldset id="myForm">
            <input type="text" required="true" /><br />
            <input type="check" required="true" /><br />
            <input type="radio" required="true" /><br />

            <input type="text" required="false" /><br />
            <input type="check" required="" /><br />
            <input type="radio"  /><br />
            <button onclick="$('#myForm').find('input[required=true]').after('<span>null</span>');">Check</button>
        </fieldset>

Answer 4

$("form[name=form_name] .required").each(function(index,e){
    if(e.value == ''){
     alert(e.name+' field is required!');   
    }
});