add javascript escape parameter to escape modifier

plugins/modifier.escape.php

@@ -37,6 +37,10 @@ function smarty_modifier_escape($string, $esc_type = 'html')
 			}
 			return $return;
 
+        case 'javascript':
+            // escape quotes and backslashes and newlines
+            return str_replace(array('\\','\'',"\r","\n"), array("\\\\", "\\'",'\r','\r'), $string);
+
         default:
             return $string;
     }