String function in query ., to check contains and replace string

hi.,

Based on drpodown box selection . , i want to display logo of concern.,

example
Corcen name can be like this

sun-123
macro-12
macro 123

Have to take the string that is present before - or empty space
like
sun
macro
macro

and all the image files are not in same format ., each and everyone is gif or tif ,jpeg... ,,How to select a image of any type keeping name alone ....

var imgctry = $('#<%= DropconList.ClientID %> option:selected').text();
imgctry = imgctry.replace(' ', '');
alert(imgctry);
var imgpath = "images/Flag/Carrier Brands" + imgctry + ".png";
$jqry('#DivBillerImg').html('

');

Thanks
Akila