html和php中下拉列表的动态填充

Question

I am working on student attendance system project for that i am using html and php I need the solution for this problem

i have 4 drop down list In the first drop down list contains Civil Engg,Comp Engg etc.....and so on. In the second dropdown list subject names are there that are stored in mssql database and depending on the value selected in first drop down I need to populate the subject from the database like

select * from allsubjects where branch='civilengg';

so please any give me the solution for this scenario

Answer 1

Here's a tutorial about Dynamic Dependent Select Box Using Ajax and jQuery that might help you

Another solution is this:

Put an id in your <select name="X"> code like <select name="X" id ="X">

Put another select like <select name="Y" id="Y">. Which will be blank.

put this jquery in your page.

$("X").on("change",function(){
    var x_value=$("X").val();
    $.ajax({
        url:'ajax.php',
        data:{subject:x_value},
        type: 'post',
        success : function(resp){
            $("#Y").html(resp);               
        },
        error : function(resp){}
    });
});

In your ajax.php add the query.

<?php
$row = mysqli_query("SELECT * from allsubjects WHERE branch =".$_POST['branch']);
while($row2 = mysqli_fetch_array($row))
    echo '<option value="' . $row2['subId'] . '">' . $row2['subName'] . '</option>
?>