Fix create graph by matrix.

script/BaseEdge.js

@@ -17,6 +17,10 @@ function BaseEdge(vertex1, vertex2, isDirect, weight, upText)
     this.useWeight = false;
     this.id        = 0;
     this.model = new EdgeModel();
+    
+    if (upText === undefined)
+        this.upText    = "";
+    else
         this.upText    = upText;
     
     if (weight !== undefined)