You are using the same ID for both anchors. You can only have one id with a given name.
id="loc" will only get the first <a> recognized.
the scr attribute does not belong in a <a> tag. It throws up errors and will get you into trouble.
Here's an easy way to do what you want [the ajax has not been checked, it don't look like it works]:
Code:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
Call your javascript jquery library here
<script type="text/javascript">
function anchor_ajax(place){
$.ajax({
url: place,
global: false,
type: "POST",
data: $("#form1").serialize(),
dataType: "html",
success: function(msg){
$("#right_col").html(msg);
},
error: function(msg) {
$("#right_col").html(msg);
}
});
}
</script>
</head>
<body>
<a href="" class="loc" onclick="anchor_ajax('index.php?where=location&id=2');">Baltimore</a><br />
<a href="" class="loc" onclick="anchor_ajax('index.php?where=location&id=1');" >New York</a><br />
</body>
</html>