Dropdownlist Onchange Show other Dropdownlist

Dropdownlist Onchange Show other Dropdownlist

function getData(dropdown) {
var value = dropdown.options[dropdown.selectedIndex].value;
if (value = 'emlak'){
document.getElementById("emlak").style.display = "block";
}
if(value = 'vasita'){
document.getElementById("vasita").style.display = "block";
}
}
HTML
<select name="kategori" onChange="getData(this);">
<option value="hat" onClick="">Hat</option>
<option value="emlak">Shirt</option>
<option value="vasita">Pants</option>
</select>
<select id="emlak" name="currentList" onChange=";" style="display:none;">
<option value="hat">Hat</option>
<option value="emlak">Shirt</option>
<option value="pants">Pants</option>
</select>
<select id="vasita" name="currentList" onChange="" style="display:none;">
<option value="hat">Otomobil</option>
<option value="emlak">Shirt</option>
<option value="pants">Pants</option>
</select>
This my first question.My Problem is i want create a category selecting
system with javascript but when i choose a option displays all divs it
should show only one div example if value = emlak show div id=emlak