基于php查询的级联下拉列表

Question

I have a dropdown which contains each day of the week.

DAYS[Monday,Tuesday,Wednesday,Thursday,Friday,Saturday,Sunday] 

I then run this query:

"SELECT DISTINCT DAY_1 FROM credit_three"

and I put the results in another drop-down, using the following code:

<select name='DAY_1' onchange="ILovePHP();">
    <?php while ($row = mysql_fetch_array($result)) {
        echo"<option value='" .$row['DAY_1']."'>". $row['DAY_1']."</option>";
    }
</select>

When the value in the dropdown changes, I need to run another query. To do so, I have tried the following:

1. On-Change I am running the function ILovePHP() , which is provided by the script:

   b= alert(b);

myfunction() was written in php like

function myfunction() {
    $sql = "SELECT TIME_1 FROM CREDIT_THREE WHERE DAY_1=DAY1";
    $result = mysql_query($sql2);
    row = mysql_fetch_array($result);
 }

But... my query isn't running. What am I doing wrong?

Answer 1

You have a typo - you are putting your query into a variable called $sql but then passing a different variable to mysql_query , " $sql2 "

$sql="SELECT TIME_1 FROM CREDIT_THREE WHERE DAY_1=DAY1";
$result=mysql_query($sql2);

Answer 2

You need to use AJAX to run the server-side function.

Try this:

<script>
function myfunction(str2) {
    var xmlhttp;
    if (window.XMLHttpRequest) {
        // code for IE7+, Firefox, Chrome, Opera, Safari
        xmlhttp=new XMLHttpRequest();
    } else {
        // code for IE6, IE5
        xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
    }

    xmlhttp.onreadystatechange = function() {
      if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
        document.getElementById("myDiv").innerHTML = xmlhttp.responseText;
      }
    }
    xmlhttp.open("GET", "ajax_info.php?q=" + str2, true);
    xmlhttp.send();
}
</script>

To set the value of str2 , you need to pass in this.value

In the ajax_info.php page, you can now code your query and the result will be shown to you in the div tag with id="mydiv" . You can do this anywhere in your front-end page, as follows:

<div id="mydiv"></div>

Now you can use the line:

echo"<option value='" .$row['DAY_1']."'>". $row['DAY_1']."</option>";

in your ajax_info.php page, and get the result you want in the div tag.

Let me know if you need any more help.

Answer 3

You need to send ajax request on change of dropdown and this ajax request will get the result from query and create html and then you need to replace html with jquery. For detail you can see the following link..

http://www.plus2net.com/php_tutorial/ajax_drop_down_list-demo.php