diff --git a/src/current/compiler/js-calc.xsl b/src/current/compiler/js-calc.xsl
index 072f9037..2fff67d5 100644
--- a/src/current/compiler/js-calc.xsl
+++ b/src/current/compiler/js-calc.xsl
@@ -40,6 +40,7 @@
             xmlns:c="http://www.lovullo.com/calc"
             xmlns:lv="http://www.lovullo.com/rater"
             xmlns:preproc="http://www.lovullo.com/rater/preproc"
+            xmlns:compiler="http://www.lovullo.com/rater/compiler"
             xmlns:calc-compiler="http://www.lovullo.com/calc/compiler">
 
 
@@ -453,7 +454,7 @@
 -->
 <template match="c:const" mode="compile-calc">
   <!-- assumed to be numeric -->
-  <value-of select="@value" />
+  <sequence select="compiler:js-number( @value )" />
 </template>
 
 
diff --git a/src/current/compiler/js.xsl b/src/current/compiler/js.xsl
index 8bf90930..78afb0c4 100644
--- a/src/current/compiler/js.xsl
+++ b/src/current/compiler/js.xsl
@@ -444,7 +444,7 @@
             <text>, </text>
           </if>
 
-          <value-of select="." />
+          <value-of select="compiler:js-number( . )" />
         </for-each>
       <text> ]</text>
     </for-each>
@@ -455,7 +455,7 @@
         <text>, </text>
       </if>
 
-      <value-of select="." />
+      <value-of select="compiler:js-number( . )" />
     </for-each>
 
   <text> ]; </text>
@@ -470,7 +470,7 @@
   <text>consts['</text>
     <value-of select="@name" />
   <text>'] = </text>
-    <value-of select="@value" />
+    <value-of select="compiler:js-number( @value )" />
   <text>;</text>
 </template>
 
@@ -529,6 +529,27 @@
 </function>
 
 
+<!--
+  Format JS numbers such that they won't be misinterpreted as octal (if they
+  have leading zeroes)
+-->
+<function name="compiler:js-number" as="xs:string?">
+  <param name="src" as="xs:string?" />
+
+  <variable name="norm" as="xs:string?"
+            select="normalize-space( $src )" />
+
+  <!-- note that this will make 0 into an empty string! -->
+  <variable name="stripped" as="xs:string"
+            select="replace( $norm, '^0+', '' )" />
+
+  <sequence select="if ( $stripped = '' ) then
+                      $norm
+                    else
+                      $stripped" />
+</function>
+
+
 <!--
   Generate code to perform a classification