function RemoveInvalidCharacters(field){
	// This function is used to remove any special characters that .NET might view as a
	// potentially dangerous request coming back to the server. So we strip them out here.
	var CleanedField='';
	var i;
	
	for(i=0; i<field.value.length; i++){
	   var c = field.value.substr(i,1);
	   // Angle braces are bad, and .NET will detect as a potentially dangerous request!
	   // and of course this has to be prevented here on the client side!
	   if( c == '<' )c='(';
	   if( c == '>' )c=')';
	   if( c == '[' )c='(';
	   if( c == ']' )c=')';
	   CleanedField+=c;
	}
	
	var regExp = /http:\/\//g;
	CleanedField = CleanedField.replace(regExp,"");

	var regExp = /https:\/\//g;
	CleanedField = CleanedField.replace(regExp,"");

	var regExp = /mailto:/g;
	CleanedField = CleanedField.replace(regExp,"");

	field.value = CleanedField;
	
}