Your not going to be able to do this with the Multiline Text field type. Anything other than RichTextMode=FullHtml won't even render the contents as HTML (i.e. you won't see the link) and if you set the field to FullHtml the HTML is altered when the item is saved...this happens with pretty much any implementation of the InputFormTextBox control.
One possible workaround is to put your javascript (...OpenDispPage) into an HTML file that you drop in the 14\Template\Layouts and then reference it in a Hyperlink field instead of Multiline field. So something like this for the URL in the Hyperlink field:
http://sharepointdev:9000/_layouts/yourfolder/test.htm?a=Table%201.1&b=table
Where the arguments to OpenDispPage are passed on the querystring and then the HTML would look something like this:
<html>
<head>
<title></title>
<script language="javascript" type="text/javascript">
OpenDispPage(getQueryString("a"), getQueryString("b"));
function getQueryString(name) {
var q = window.location.search.substring(1);
var qs = q.split("&");
for (var i = 0; i < qs.length; i++) {
var parts = qs[i].split("=");
if (parts[0] == name)
return parts[1];
}
return null;
}
function OpenDispPage(a, b) {
alert(a + "," + b);
}
</script>
</head>
<body>
</body>
I think that's pretty clean, but without knowing exactly what you're trying to do I may be way off.