看看运行后为什么不能显示？
哪位看看以下的程序为什么运行后什么都不显示？<html>
<head>
<title>
company objects program
</title>
<script language=javascript>
function Company()
{
,inc.";
services";
}
function Sales()
{
this.territory="north america";
this.sales_reps="50";
}
Sales.prototype=new Company();
function Production()
{
this.facilities="new york chicago,and los angeles";
this.personnel="100";
}
Production.prototype=new Company();
</script>
</head>
<body>
<script language=javascript>
sales_object=new Sales();
document.writeln(sales_);
document.writeln("Producer of"+sales_);
document.write("with"+sales_object.sales_reps+"sales reps");
document.writeln("in"+sales_object.territory);
production_object=new Production();
document.write(production_);
document.writeln("has"+production_object.personnel+"production personnel");
document.write("with facilities in"+production_object.facilities);
<script>
</body>
</html>
