ajax verification username and password, ajax verification username_PHP tutorial

<span><span> 1</span>     <span>var</span> user = form.name.<span>value;
</span><span> 2</span>     <span>var</span> password = form.password.<span>value;
</span><span> 3</span>     <span>var</span> url = "chkname.php?user="+user+"&password="+password;<span>//</span><span>以前只知道ajax用于对用户名的检测，原来还可以对密码进行检测。</span>
<span> 4</span>     xmlhttp.open("GET",url,<span>true</span><span>);
</span><span> 5</span>     xmlhttp.onreadystatechange = <span>function</span><span>(){
</span><span> 6</span>     <span>if</span>(xmlhttp.readyState == 4<span>){
</span><span> 7</span>             <span>var</span> msg = xmlhttp.<span>responseText;
</span><span> 8</span>             <span>if</span>(msg == '1'<span>){
</span><span> 9</span>                 alert('用户名或密码错误!!'<span>);
</span><span>10</span>                 form.password.<span>select();
</span><span>11</span>                 form.check.value = ''<span>;
</span><span>12</span> <span>                code(form);
</span><span>13</span>                 <span>return</span> <span>false</span><span>;
</span><span>14</span>             }<span>if</span>(msg == "3"<span>){
</span><span>15</span>                 alert("用户名被占用，请重新输入！"<span>);
</span><span>16</span>                 <span>return</span> <span>false</span><span>;
</span><span>17</span>             }<span>else</span><span>{
</span><span>18</span>                 alert('欢迎光临'<span>);
</span><span>19</span>                 location.<span>reload();
</span><span>20</span> <span>            }
</span><span>21</span> <span>        }
</span><span>22</span> <span>    }
</span><span>23</span>     xmlhttp.send(<span>null</span><span>);
</span><span>24</span>     <span>return</span> <span>false</span>;</span>