IE6, IE7, and Firefox Javascript do not prompt to close the window code

1st methods:
IE6: <textarea id="runcode45991"></textarea>
[Ctrl + A select all Note: If you need to introduce external JS, You need to refresh it to execute]

IE7:
[Ctrl + A select all Note: If you need to introduce external JS, You need to refresh it to execute]

IE6, IE7, FF GeneralCode:

[Ctrl + A select all Note: If you need to introduce external JS, You need to refresh it to execute]

2nd methods:
<! -- The default close method in IE. in IE, a dialog box is displayed for confirmation. -->
<A href = "javascript: window. Close ()"> default close </a>
<! -- In IE6, window. opener can be used to bypass this restriction -->
<A href = "javascript: window. operner =" X "; window. Close ()"> close IE6 </a>
<! -- This method can be used in IE7 -->
<A href = "javascript: window. Open ('', '_ top'); window. Top. Close (); "> close IE7 </a>