how to get context from digital signature

Hello,
 I have digital signature in asp.net. I want to get context with was signing.
 I search goolge, but i can't find. I want to use x509 or others component. Getting context using capicom i Have, but signature created by mozilla firefox doesn't work. Please help me
 
This script was used to signing:
StringBuilder sb = new StringBuilder(); sb.Append("<script language=\"javascript\"> \n");
sb.Append("funct ...