如何从下拉列表中获取选定的值并使用它来显示另一个表单？

Question

I am new to PHP, Yii-framework and web programming in general.

So I have some difficulties in writing simple registration form.

I have tables Persons, Categories, Properties, CategoryProperties, PropertyValues:

Persons ( name, category_id)
Categories(category_id, category_name)
Properties(propety_id, property_name)
CategoryProperties(category_id, property_id)
PropertyValues(property_id, category_id, person_id, some_value)

For example, category_name = 'teacher', property='work experience', some_value='15'.

Depending on which category was selected we should display block with properties matching that category.

How to get selected value from dropdown list (Categories) and use it to display another form which depends on that value and other database table?

So far I have only this

<div class="form">
<?php $form=$this->beginWidget('CActiveForm', array(
    'id'=>'login-form',
    'enableClientValidation'=>true,
    'clientOptions'=>array(
        'validateOnSubmit'=>true,
    ),
)); ?>

<p class="note">Fields with <span class="required">*</span> are required.</p>
<div class="row">
        <?php echo $form->labelEx($model,'name'); ?>
        <?php echo $form->textField($model,'name'); ?>
        <?php echo $form->error($model,'name'); ?>
</div>
<div class="row">
    <?php echo $form->labelEx($model,'category'); ?>
    <?php 
    echo $form->dropDownList($model,'category', 
    Categories::model()->getAssocList(),  array('empty'=>'Select category')?>
    <?php echo $form->error($model,'category'); ?>
</div>
<div class="row buttons">
    <?php echo CHtml::submitButton('AddReader'); ?>
</div>

<?php $this->endWidget(); ?>
</div><!-- form -->

Answer 1

Not sure if I got it right, are you trying to update a second combo once the first was modified using php? if so, you can't.

You have to use JavaScript and if you are using a database, probably Ajax.

Remember PHP is a server side language, you have to post your form again to update it. That's why you should use javascript, that runs on the browser.