Get index value from dropdown form - php

Question

I have a dropdown that is filled by a database and everything works well. However I want to pass a parameter to php based on the value of the dropdown which I can do. If I force the var to have a particular number it gets the corresponding item in the database. I'm having a problem to get the value of a dropdown. I've tried all the suggestions here in the forum and nothing works in this particular area of my code. I have it working on another piece of my code but not on this particular one and I don't know why. Here is my code:
<select id="servicos" onChange="return selectServ();">
<option value="item" class="itemoption">Serviço</option>
This is the code that is not working:
function selectServ() {
var e = document.getElementById("servicos");
var idserv = e.options[e.selectedIndex].value;
$.getJSON("http://ib.esy.es/gestao/_php/servicos_threadingpreco.php", { serv: idserv }, null).then(function(data) {
console.log(data);
var tr = data
for (var i = 0; i < data.length; i++) {
var tr = $('<tr/>');
// Indexing into data.report for each td element
$(tr).append("<td>" + data[i].preco + "</td>");
$('.table1').append(tr);
}
});
}
If I put
var idserv = "1"
It is working, however this:
var e = document.getElementById("servicos");
var idserv = e.options[e.selectedIndex].value;
Is not getting a value. The console log gives:
selectdynamicpreco.html:76 Uncaught TypeError: $(...).value is not a function

Answer 1

You should consider using jQuery to get the value of the dropdown:
$('#dropdown').val() will give you the selected value of the drop down element. Use this to get the selected options text.
$("#dropdown option:selected").text();
Should get you the text value of the dropdown.

Answer 2

This is working on another piece of the code
<script>
function selectCat(){
$('#servicos').change(function() {
$('#demo').text($(this).find(":selected").text());
});
//for textbox use $('#txtEntry2').val($(this).find(":selected").text());
var e = document.getElementById("categoria");
var servSelected = e.options[e.selectedIndex].value;
var url = "";
var items="";
if(servSelected === "1"){
url = "http://ib.esy.es/gestao/_php/servicos_threading.php";
}
if(servSelected === "2"){
url = "http://ib.esy.es/gestao/_php/servicos_sobrancelhas.php";
}
if(servSelected === "3"){
url = "http://ib.esy.es/gestao/_php/servicos_manicure.php";
}
$.getJSON(url,function(data){
$.each(data,function(index,item)
{
items+="<option value='"+item.ID+"'>"+item.servico+"</option>";
});
$("#servicos").html(items);
});
};
</script>