使用JavaScript onchange的下拉菜单不起作用

Question

I have a simple drop down and I want to have it so that if the user selects "STUDENT", it will display Student data from mysql. But the page stays the same (it show's the "STUDENT" for one second and back to the original page),and this isn't working. Can someone please help.

Below is my code:

<th width="20%">View&nbsp;Type:&nbsp;&nbsp;&nbsp;&nbsp;
            <form action="index.php" method="post" id="form1">
            <select  name="value1" onchange="document.forms.form1.submit();">
                    <option value="all">All('.$count.')</option>
                    <option value="student">STUDENT('.$stucount.')</option>
                    <option value="faculty">FACULTY('.$facount.')</option>
               </select>  

 </form>       
    </tr>
';  

Answer 1

try this:

<select  name="value1" onchange="this.form.submit()">

all $_post should be $_POST .

$_POST is a super global variable and all variables in php are case sensitive.

Set post data in your option and check the post data and set select one option. Try this :

<select  name="value1" onchange="this.form.submit()">
            <option <?php echo (isset($_POST['value1']) && $_POST['value1'] == 'all')? 'selected="selected"' :  ''; ?> value="all">All('.$count.')</option>
            <option <?php echo (isset($_POST['value1']) && $_POST['value1'] == 'student')? 'selected="selected"' :  ''; ?>  value="student">STUDENT('.$stucount.')</option>
            <option <?php echo (isset($_POST['value1']) && $_POST['value1'] == 'faculty')? 'selected="selected"' :  ''; ?> value="faculty">FACULTY('.$facount.')</option>
</select>

Answer 2

Apart from the answer posted by Awlad try this for your second problem. Your code is not complete by the way, so before you echo the above form place this:

$value = (isset($_POST['value1'])) ? $_POST['value1'] : '';

And replace with this:

<th width="20%">View&nbsp;Type:&nbsp;&nbsp;&nbsp;&nbsp;
            <form action="index.php" method="post" id="form1">
            <select  name="value1" onchange="document.forms.form1.submit();">
                    <option value="all"'.($value=="all"?"selected":"").'>All('.$count.')</option>
                    <option value="student"'.($value=="student"?"selected":"").'>STUDENT('.$stucount.')</option>
                    <option value="faculty"'.($value=="faculty"?"selected":"").'>FACULTY('.$facount.')</option>
               </select>  

 </form>       
    </tr>
'; 

$value saves the POST value sent, once you click on the dropdown and based on that value, the respective option will be selected.