如果字段为空，则需要 Jquery 验证下拉列表

Question

如果 #category 字段为空，我会尝试将下拉列表设为必需。

谢谢!

JQUERY 尝试#1:

$("#uploadDocsForm").validate({
    rules: {
        name: {
            required: true,
            minlength: 2,
            maxlength: 255  
        },
        cat_id: {
            required: function(element) {
                return $("#category").val() == '';
            }
        }
    },
    messages: {
        name: 'Please enter a <b>Document Name</b>.',
        cat_id: 'Please select a <b>Category</b>.'
    }
});

JQUERY 尝试#2:

$("#uploadDocsForm").validate({
    rules: {
        name: {
            required: true,
            minlength: 2,
            maxlength: 255  
        },
        cat_id: {
            required: {
                depends: function(element) {
                    return $("#category").val() == '';
                }
            }
        }
    },
    messages: {
        name: 'Please enter a <b>Document Name</b>.',
        cat_id: 'Please select a <b>Category</b>.'
    }
});

HTML:

<form name="uploadDocsForm" id="uploadDocsForm">   
    <label for="name">Document Name</label>
    <input name="name" id="name" type="text" class="textbox"/>
    <label for="cat_id">Category</label>
    <select name="cat_id" id="cat_id" class="dropdown">
    <option selected>Please Select Category</option>
    <option>------------------------</option>
    <option value="1">test cat</option>
    </select>
    <label for="category">New Category</label>
    <input name="category" id="category" type="text" class="textbox"/>
    </form>

Answer 1

$("#uploadDocsForm").validate({
    rules: {
        name: {
            required: true,
            minlength: 2,
            maxlength: 255  
        },
        cat_id: {
            required: {
                depends: function(element) {
                    return $("#category").val() == '';
                }
            }
        }
    },
    messages: {
        name: 'Please enter a <b>Document Name</b>.',
        cat_id: 'Please select a <b>Category</b>.'
    }
});

depends 函数现在检查类别元素是否已填充，如果是，则需要第二个元素。否则是可选的(意思是可以填充)。

用例:

• 类别已填，cat_id 为空:无效
• 已填写类别，已填写cat_id:有效
• 类别为空，cat_id 为空:有效
• 类别为空，cat_id 已填充:有效