AJAX实例：根据邮编自动完成地址信息
<p><STRONG>描述：</STRONG> <P></P>在注册或购物车结帐的时候，需要用户填入个人资料，这个环节可以简练一下，我们只需客人填入邮政编码，然后就根据这个邮政编码，自动从<a href="http://www.phpchina.com/javascript:;" onClick="javascript:tagshow(event, '%CA%FD%BE%DD%BF%E2');" target="_self"><u><strong>数据库</strong></u></a>中取出相应的省，市等地址信息。这样既可以减少客户的输入，增加客户体验，又可以减少由于资料输入而产生的错误。 <P></P><STRONG>实现：</STRONG> <P></P><P></P><CODE><FONT face=新宋体><a href="http://www.phpchina.com/javascript:;" onClick="javascript:tagshow(event, 'HTML');" target="_self"><u><strong>HTML</strong></u></a> <BR>＜script><BR>function createRequestObject() { <BR>var ro; <BR>var browser = navigator.appName; <BR>if(browser == "Microsoft <a href="http://www.phpchina.com/javascript:;" onClick="javascript:tagshow(event, 'Internet');" target="_self"><u><strong>Internet</strong></u></a> Explorer"){ <BR>ro = new ActiveXObject("Microsoft.XMLHTTP"); <BR>}else{ <BR>ro = new XMLHttpRequest(); <BR>} <BR>return ro; <BR>} <BR>var http = createRequestObject(); <BR>function sndReq(zip) { <BR>http.open('get', 'zipcode.php?zip='+zip); <BR>http.onreadystatechange = handleResponse; <BR>http.send(null); <BR>} </FONT></CODE><CODE><FONT face=新宋体>function handleResponse() { <BR>if(http.readyState == 4){ <BR>var response = http.responseText; <BR>var update = new Array(); <BR>if(response.indexOf('|' != -1)) { <BR>update = response.split('|'); <BR>document.getElementById("city").value = update[0]; <BR>document.getElementById("state").value = update[1]; <BR>} <BR>} <BR>} <BR>＜/script><BR>＜h3>Enter A United States Zipcode, Then Tab＜/h3><BR>＜table align="center"><BR>＜tr><BR>＜td>Enter Zipcode:＜/td><BR>＜td>＜input type="text" id="zipcode" name="zipcode" onBlur="sndReq(this.value);"/>＜/td><BR>＜/tr><BR>＜tr><BR>＜td>City:＜/td><BR>＜td>＜input type="text" id="city" name="city"/>＜/td><BR>＜/tr><BR>＜tr><BR>＜td>State:＜/td><BR>＜td>＜input type="text" id="state" name="state"/>＜/td><BR>＜/tr><BR>＜/table></FONT></CODE> 以上是客户输入页面，下面是服务端的处理页面'zipcode.php <P></P><CODE><?php<br /><FONT face=新宋体>$dbuser = 'root';<BR>$dbpass = '111111';<BR>$cn = mysql_connect("localhost", $dbuser, $dbpass);<BR>$db = mysql_select_db("<a href="http://www.phpchina.com/javascript:;" onClick="javascript:tagshow(event, 'ajax');" target="_self"><u><strong>ajax</strong></u></a>\");<BR>$sql = "select city, state from zipcodes where zipcode = " . $_REQUEST['zip'];<BR>$rs = mysql_query($sql);<BR>$row = mysql_fetch_array($rs);<BR>echo $row['city'] . "|" . $row['state'];<BR>mysql_close($cn);<BR>?></FONT></CODE> 当客户输入一个POSTCODE后，zipcode.php就接收到它，然后进行从数据表中取出对应的资料，再按一定的格式返回给客户端（此处是以 | 分隔）。最后客户端接收返回的资料，显示在页面上。 <P></P><CODE><FONT face=新宋体>if(response.indexOf('|' != -1)) {<BR>update = response.split('|');<BR>document.getElementById("city").value = update[0];<BR>document.getElementById("state").value = update[1];<BR>}</FONT></CODE></FONT></p> <center><input type="image" onclick=copyToClipBoard() src="http://www.phpchina.com/images/phpcn_book_bu_tj.gif" border="0"></center>
