4 files changed, 7 insertions, 6 deletions

diff --git a/js/Color.js b/js/Color.js
index e294f65..066e1a1 100644
--- a/js/Color.js
+++ b/js/Color.js
@@ -24,10 +24,10 @@
  */
 var ColorError = function (message)
 {
-    this.prototype = Error.prototype;
     this.name = "ColorError";
     this.message = (message) ? message : "Error";
 };
+ColorError.prototype = new Error();
 
 /**
  * Color
diff --git a/js/RrdGraph.js b/js/RrdGraph.js
index 48b9814..a3b0124 100644
--- a/js/RrdGraph.js
+++ b/js/RrdGraph.js
@@ -27,10 +27,10 @@
  */
 var RrdGraphDescError = function (message)
 {
-    this.prototype = Error.prototype;
     this.name = "RrdGraphDescError";
     this.message = (message) ? message : "Error";
 };
+RrdGraphDescError.prototype = new Error();
 
 /**
  * RrdGraphDesc
@@ -393,10 +393,11 @@ RrdGraphDesc.prototype.hrule = function (graph, value, color, legend)
  */
 var RrdVdefError = function (message)
 {
-    this.prototype = Error.prototype;
     this.name = "RrdVdefError";
     this.message = (message) ? message : "Error";
 };
+RrdVdefError.prototype = new Error();
+
 
 /**
  * RrdVdef
@@ -694,10 +695,10 @@ RrdVdef.prototype.calc = function(src)
  */
 var RrdGraphError = function (message)
 {
-    this.prototype = Error.prototype;
     this.name = "RrdGraphError";
     this.message = (message) ? message : "Error";
 };
+RrdGraphError.prototype = new Error();
 
 /**
  * RrdGraph
diff --git a/js/RrdRpn.js b/js/RrdRpn.js
index 5ca8daf..3eb4e4a 100644
--- a/js/RrdRpn.js
+++ b/js/RrdRpn.js
@@ -27,10 +27,10 @@
  */
 var RrdRpnError = function (message) 
 {
-    this.prototype = Error.prototype;
     this.name = "RrdRpnError";
     this.message = (message) ? message : "RPN stack underflow";
 };
+RrdRpnError.prototype = new Error();
 
 /**
  * RrdRpn
diff --git a/js/RrdTime.js b/js/RrdTime.js
index c1de1fc..9010ece 100644
--- a/js/RrdTime.js
+++ b/js/RrdTime.js
@@ -27,10 +27,10 @@
  */
 var RrdTimeError = function (message)
 {
-        this.prototype = Error.prototype;
         this.name = "RrdTimeError";
         this.message = (message) ? message : "Error";
 };
+RrdTimeError.prototype = new Error();
 
 /**
  * RrdTime