Dynamic menus using onchange and databases.

<!--- store the selected Main_Group variable variable after the first select boxes submits itself --->
<cfif isDefined('url.manufacturerid')>
    <cfset url.manufacturerid = url.manufacturerid>
</cfif>
<!--- test if staement--->
<cfif isDefined('url.modelid')>
	<cfset url.modelid = url.manufacturerid>
</cfif>
<cfif isDefined('url.specid')>
	<cfset url.specid = url.specid>
</cfif>
<!---end of test if statement--->
 
<cfoutput>
  <form name="DropDown" method="post">
  <!--- query DB for the first drop down list --->
  <cfquery name="get_Manufacturer" datasource="quote-system">
     SELECT *
     FROM manufacturer_table
  </cfquery>
 
 
  <!--- first drop down list --->
  <!--- NOTICE the onChange javascript event in the select tag, this is what submits the form after the first selection --->
  <select name="select_Manufacturer" required="yes" onchange="window.open(this.options[this.selectedIndex].value,'_self')">
     <option>Select Manufacturer</option>
     <!--- dynamically populate the first drop down list based on the get_Main_Group query --->
     <!--- NOTICE the CFIF within the option tag, this says, if the first selection has been made, display the chosen option when the page reloads --->
     <cfloop query="get_Manufacturer">
         <option value="new.cfm?manufacturerid=#get_Manufacturer.manufacturer_ID#&manu_value=#get_Manufacturer.number#.html" <cfif isDefined('url.manufacturerid')><cfif url.manufacturerid eq "#cost#">selected</cfif></cfif>>#manufacturer_ID#</option>
     </cfloop>
</select>
<p>
<!--- if the first selection has been made, display the second drop down list with the appropriate results --->
<cfif isDefined('url.manufacturerid')>
   <!--- query DB for second drop down list, based on the selected item from the first list --->
   <cfquery name="get_Model" datasource="quote-system">
        SELECT *
        FROM model_table 
        WHERE sub_manufacturer_ID = <cfqueryparam value="#url.manufacturerid#" cfsqltype="cf_sql_varchar">
   </cfquery>
   <!--- second drop down list --->
   <select name="select_Model" required="yes" onchange="window.open(this.options[this.selectedIndex].value,'_self')">
      <option>Select Model</option>
      <!--- dynamically populate the second drop down list based on the get_Sub_Group query --->
      <cfloop query="get_Model">
         <option value="#new.cfm?modelid=#get_Model.manufacturer_ID#&manu_value=#get_Model.number#.html#" <cfif isDefined('url.modelid')><cfif url.modelid eq "#cost#">selected</cfif></cfif>>#model_ID#</option>
      </cfloop>
   </select>
</cfif>
<p>
<!---start of third testing drop down--->
<cfif isDefined('url.modelid')>
<cfquery name="get_Spec" datasource="quote-system">
SELECT *
FROM spec_table
WHERE sub_model_ID = <cfqueryparam value="#url.modelid#" cfsqltype="cf_sql_varchar">
</cfquery>
   <select name="select_Spec" required="yes" onchange="window.open(this.options[this.selectedIndex].value,'_self')">
      <option>Select Spec</option>
      <!--- dynamically populate the second drop down list based on the get_Sub_Group query --->
      <cfloop query="get_Spec">
         <option value="#new.cfm?specid=#get_Spec.model_ID#&manu_value=#get_Spec.number#.html#" <cfif isDefined('url.specid')><cfif url.specid eq "#cost#">selected</cfif></cfif>>#spec_ID#</option>
      </cfloop>
   </select>
</cfif>
<!---end of test third drop down box --->
</form>
</cfoutput>
                                              

1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:
14:
15:
16:
17:
18:
19:
20:
21:
22:
23:
24:
25:
26:
27:
28:
29:
30:
31:
32:
33:
34:
35:
36:
37:
38:
39:
40:
41:
42:
43:
44:
45:
46:
47:
48:
49:
50:
51:
52:
53:
54:
55:
56:
57:
58:
59:
60:
61:
62:
63:
64:
65:
66:
67:
68:
69: