A practical MySQL Ajax PHP cascade three cascade pull-down frame

http://blog.sina.com.cn/s/blog_5ffc4bac0100jgms.html

1, yesterday made a simple cascade three cascade drop-down box. Super practical.

index.php:
[code]
.lt; html.gt;
.lt; head.gt;
.lt; meta. Src=.quot; aa.js.quot;.Gt;.Lt; /script.gt;
.lt; /head.gt;
.lt; body.gt; mysql_select_db. BY `id` ASC.quot;
$result = mysql_query ($str) or die (.Quot; Invalid query:). #93;}.lt; /option.gt;
EOD;
}
}
mysql_close ($conn);
.Gt. /option.gt;
.Lt; /select.gt;
.lt; /label.gt;

.lt; Uot; send value.quot; onClick=.quot; alert (document.getElementByIdx ('sel').Options.#91; document.getElementByIdx ('sel').SelectedIndex.#93;.Text ''. .#91; document.getElementByIdx ('sel3').SelectedIndex.#93;.Text).Quot;.Gt;
.lt; /body.gt;
.lt;