diff --git a/po2js.pl b/po2js.pl
index 93c10c1..ffe2e20 100755
--- a/po2js.pl
+++ b/po2js.pl
@@ -82,11 +82,13 @@ my $outfile = $options->{o};
 $content .= "// Proxmox Message Catalog: $outfile\n" if $outfile;
 
 $content .= <<__EOD;
-const __proxmox_i18n_msgcat__ = $json;
+__proxmox_i18n_msgcat__ = $json;
 
 function fnv31a(text) {
-    let hval = 0x811c9dc5;
-    for (const c of text) {
+    var len = text.length;
+    var hval = 0x811c9dc5;
+    for (var i = 0; i < len; i++) {
+	var c = text.charCodeAt(i);
 	hval ^= c;
 	hval += (hval << 1) + (hval << 4) + (hval << 7) + (hval << 8) + (hval << 24);
     }
@@ -95,8 +97,12 @@ function fnv31a(text) {
 }
 
 function gettext(buf) {
-    let digest = fnv31a(buf);
-    return __proxmox_i18n_msgcat__[digest]?.[0] ?? buf;
+    var digest = fnv31a(buf);
+    var data = __proxmox_i18n_msgcat__[digest];
+    if (!data) {
+	return buf;
+    }
+    return data[0] || buf;
 }
 __EOD