How to populate dependable drop-down using Ajax and php [closed]

Answer 1

Yes, check following jquery ajax code. In this example, if you change "Department" then it will populate the listing of "Name" dropdown.

$(document).on("change", '#department', function(e) {
            var department = $(this).val();
            

            $.ajax({
                type: "POST",
                data: {department: department},
                url: 'admin/users/get_name_list.php',
                dataType: 'json',
                success: function(json) {

                    var $el = $("#name");
                    $el.empty(); // remove old options
                    $el.append($("<option></option>")
                            .attr("value", '').text('Please Select'));
                    $.each(json, function(value, key) {
                        $el.append($("<option></option>")
                                .attr("value", value).text(key));
                    });														
	                

                    
                    
                }
            });

        });

Answer 2

Although there are many codes available out there. I am writing most easy and basic code for you.

HTML

<select id="id" onchange="update_name(this.id)"></select>

AJAX Code

function update_name(id)
{

    var xmlhttp=new XMLHttpRequest();
     xmlhttp.onreadystatechange=function()
{
    if (xmlhttp.readyState==4 && xmlhttp.status==200)
    {
     document.getElementById("txt").innerHTML=xmlhttp.responseText;
     }
 }
    xmlhttp.open("GET","update_data.php?q="+id,true);
    xmlhttp.send();
}

update_data.php (PHP code)

<?php
   if(isset($_GET['q'])
    {
            $id= $_GET['q'];
             //based on id run your query
    }

Answer 3

given select1 and select2 like this:

<select id="select1">
    <option id="11" value="x">X</option>
    <option id="12" value="y">Y</option>
</select>
<select id="select2">
    <option id="21" value="1">1</option>
    <option id="22" value="2">2</option>
</select>

then you can do something like this with jQuery:

$('#select1').on('change', function() {
    $.ajax({
        url: "test.html",
    }).done(function(response) {
        $('#select2').html(response);
});

This assumes your ajax call returns a string like

<option id="21" value="3">3</option><option id="22" value="4">4</option>

from your server sided file. If you return a json you have to decode it first, but this is the general gist of it. Take a look at the jQuery ajax() function

Answer 4

I guess you can do this:

make a global function which accepts two args, currElem, nextElem and dataObj:

function dynoDropdowns(currElem, nxtElem, dataObj){
    $.ajax({
        url:"path/to/file",
        type:"post",
        data:dataObj,
        dataType:"json", // <-------------expecting json from php
        success:function(data){
           $(nxtElem).empty(); // empty the field first here.
           $.each(data, function(i, obj){
               $('<option />',
               {
                   value:obj.value,
                   text:obj.text
               }
                ).appendTo(nxtElem);
           });
        },
        error:function(err){
           console.log(err);
        }
    });
}

now your change events are:

$(function(){
    $('select').on('change', function(e){
        if(this.id === "id"){
          var dataObj = {id:this.value};
          dynoDropdowns(this, '#name', dataObj);
        }else if(this.id === "name"){
          var dataObj = {name:this.value};
          dynoDropdowns(this, '#department', dataObj);
        }
    });
});