Php multiple search dropdowns - php

Question

I'm having hard time, thinking out how can I make a PHP dropdown search for a real estate website.
So I have made the MYSQL cities and properties but I don't know how to make the categories and when you search like a Mobile Phone to come another dropdown menu and to select the phone model and to display the results in another page.
the cities list: http://prikachi.com/images.php?images/747/7206747u.jpg
the property type: http://prikachi.com/images/776/7206776v.jpg
p.s. sorry but I could post it like codes..

Answer 1

Use Ajax with PHP by onchange event.
as:
<select id='drpdwn1' onchange='getdata(this.value)'>
<option value='-1'>Please Select</option>
<option value='1'>Example1</option>
<option value='2'>Example2</option>
</select>
<select id='drpdwn2' onchange='getdata(this.value)'>
<option value='-1'>Please Select</option>
</select>
//
<script src="http://code.jquery.com/jquery-1.11.3.js" ></script>
<script>
function getdata(value){
jQuery("#drpdwn2").html("<option>Some Option</option>");
}
function getdatabyAjax(value){
$.post('URL_here',{param:value},function(data){
jQuery("#drpdwn2").html(data);
});
}
</script>
//
when user select example1, javascript getdata() will be called and by ajax, value will be redirected to drpdwn2.