Working too hard.
Code:
<!DOCTYPE html>
<html>
<body>
<form id="frm">
<select name="dropdown">
<option value="0">Select a Date</option>
<option value="15">15 Days from Now</option>
<option value="30">30 Days from Now</option>
<option value="45">45 Days from Now</option>
<option value="60">60 Days from Now</option>
</select>
<input type="text" name="mytext" size=60>
</form>
<script type="text/javascript">
(
function( )
{
var form = document.getElementById("frm");
var mytextbox = form.mytext;
var mydropdown = form.dropdown;
mydropdown.onchange =
function( )
{
var theDate = new Date();
theDate.setDate( theDate.getDate() + Number(this.value) );
var pretty = (theDate.getMonth()+1) + "/" + theDate.getDate() + "/" + theDate.getFullYear();
mytextbox.value = pretty;
}
}
)( );
</script>
</body>
</html>
Change the code for
pretty to format the date however you want it.