<!DOCTYPE html>
<html>
<body>
<iframe name="frameLayout" frameborder="0" width="200px" height="200px">
</iframe>
<form id="frm1" action="demo-form.php" target="frameLayout">
First name: <input type="text" name="fname" value="Donald"><br>
Last name: <input type="text" name="lname" value="Duck"><br>
<input type="submit" value="Submit">
</form>
<p>The value of the action attribute is:
<script>
document.write(document.getElementById("frm1").action);
</script>
</p>
</body>
</html>
原文：http://9966064.blog.51cto.com/9956064/1649675