How to get <select> value with javascript?

Question

How to get value from and send it through php? It's okay with text input but I can't get value. I just need to send values through email via ajax and php.

html code

<div class="input">
<input type="text" name="height" placeholder=""/>
</div>
    <div class="input">
        <select name="select">
            <option value="1">one</option>
            <option value="2">two</option>
        </select>
</div>
<div class="input">
    <select name="selectt">
        <option value="3">three</option>
        <option value="4">four</option>
</select>

js code

var user_height = $(this).find("input[name='height']").val();

var user_select = $(this).find("input[name='select']").val();
var user_selectt = $(this).find("input[name='selectt']").val();
var ok_send = $(this).find('.results_send_form');
//getting values
$.ajax({
    url: "send.php",
    type: "post", 
    dataType: "json", 
    data: { 
        "height": user_height,
        "select": user_select,
        "selectt": user_selectt,
    }  

Answer 1

Replace your code

var user_height = $(this).find("input[name='height']").val();
var user_select = $(this).find("input[name='select']").val();
var user_selectt = $(this).find("input[name='selectt']").val();

to

var user_height = $(this).find("input[name='height']:selected").val();
var user_select = $(this).find("input[name='select']:selected").val();
var user_selectt = $(this).find("input[name='selectt']:selected").val();

Answer 2

You don't have an input named select or selectt , these are select menus. I don't know what this refers to in your code since you didn't include the context, but you would need to use select[name='select'] or select[name='selectt'] .