配列要素を文字列にするには
<html>
<head>
<title>Sample</title>
</head>
<body>
<script type="text/javascript"><!--
colorName = ["黒色","青色","赤色","紫色","緑色","水色","黄色","白色"];
ary = colorName.toString();
document.write(ary,"<br>");
// --></script>
</body>
</html>
説明などは本書を参考にしてください。