c# - Google maps api in updatepanel - HTML in InfoWindow do not show up on refreshing update panel -

i have google map canvas inside update panel. map refreshes content(location) every time update panel refreshes. need show content in tabular format in infowindow.
problem if use html tags in infowindow shows first time when application loads , when refreshing update panel application freezes. if use plain strings in infowindow content shows every time.
here's code in c# generating tabular content of infowindow.

sb.append("<div id=\"content\"><table>"); foreach (datarow dr in dt.rows) {     sb.appendline("<tr><td>" + dr[0].tostring() + "</td></tr>"); } sb.append("</table></div>"); 

this doesnt works after updating update panel. below code works:

stringbuilder sb = new stringbuilder(); foreach (datarow dr in dt.rows) {     sb.appendline(dr[0].tostring()); }  

i putting generated string hiddenfield , using in js file this:

var contentstring = document.getelementbyid('infowindowstring').value;  var infowindow = new google.maps.infowindow({     content: contentstring })   

can 1 please tell me going wrong.

i checked javascript console in browser , found error message a potentially dangerous request.form value detected client
using following stackoverflow links - this , this found validaterequest set false in page directive: validaterequest="false"

hope helps else facing same problem.