php - How to get VALUE from FORM without Submitting it?

Question

I would like to get value from Form without submitting it, because the client have to choose the right type of house model to get the right form that fits the selected house model, without submitting, just selecting the house model and it for example continues the rest of form after that.

I have so far tried with this:

<form method="GET" action="foo.php">
  <select name="house_model">
    <option value="">------</option>
    <option value="<?php echo $model1;?>">Model 1</option>
    <option value="<?php echo $model2;?>">Model 2</option>
    <option value="<?php echo $model3;?>">Model 3</option>
  </select>
</form>

<?php    
$a = $_GET["housemodel"];

if($a<>'')
{
if($a == $model1)
{
   echo "<input type="text" name="a" value="something model1">";
}
else if($a == $model2)
{
   echo "<input type="text" name="b" value="something model2">";
} 
else if($a == $model3)
{
   echo "<input type="text" name="c" value="something model3">";
}
}
?>        

Answer 1

I think, if you dont want page to be refreshed when user selects value from your drop down list, then you can use ajax. AJAX is used for this purpose. if you google, then you will find lots of tutorials related to AJAX.