Request Validation has detected a potentially dangerous client input value, and processing of the request has been aborted. ...

Request Validation has detected a potentially dangerous client input value, and processing of the request has been aborted.  This value may indicate an attempt to compromise the security of your application, such as a cross-site scripting attack.  To allow pages to override application request validation settings, set the requestValidationMode attribute in the httpRuntime configuration section to requestValidationMode="2.0". Example: . After setting this value, you can then disable request validation by setting validateRequest="false" in the Page directive or in the  configuration section.  However, it is strongly recommended that your application explicitly check all inputs in this case.  For more information, see http://go.microsoft.com/fwlink/?LinkId=153133.