Get value from <select>

How do you get the value of selected item in a custom dropdown list?

I want to select the item, then when a button is clicked return the value of the drop down
I create the dropdown from the following code
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$str = "";
//select values from database

$str.= "<select name=\"JobDropDown\"><option value=\"Please Select\">";

global $conn;

$strSQL = "select Job_Name, CompanyID from Jobs";

$rs = db_query($strSQL,$conn);
while ($data = db_fetch_array($rs)){

if ($data["CompanyID"] == $_SESSION["_Contractor_Jobs_OwnerID"]){

$str.="<option value=\"".$data["Job_Name"]."\">".$data["Job_Name"]."</option>";

}//end if ($data ["CompanyID"] yadda yadda

}//end while ($data =db_fetch_array($rs))

$str.="</select>";

echo $str;
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I tried inserting a button, and do a simple $result["txt"] = ... but dunno what to set it equal to
Thanks