I have got my solution like this..
The JQgrid column shold be defined like this:
colNames: ['Site_Name', 'Details'],
colModel: [{ name: 'Site_Name', index: 'Site_Name', width: 130,editable: false, sortable: false,formatter: 'showlink', formatoptions: { baseLinkUrl: 'javascript:', showAction: "Link('", addParam: "');"} },
{ name: 'Details', index: 'Details', width: 400, editable: false, sortable: false }],
The Javascript function:
function Link(id) {
var row = id.split("=");
var row_ID = row[1];
var sitename= $("#users_grid").getCell(row_ID, 'Site_Name');
var url = "http://"+sitename; // sitename will be like google.com or yahoo.com
window.open(url);
}
Thats it..