Ajax实现注册无刷新验证用户名是否存在
//创建一个方法来根据浏览器的版本 创建ajax对象
function createxhr(){
//如何进行方法的赛选
if(window.XMLHttpRequest){
var xhr = new XMLHttpRequest();
} else {
var version =
["Msxml2.XMLHTTP.6.0","Msxml2.XMLHTTP.5.0","Msxml2.XMLHTTP.4.0","Msxm
l2.XMLHTTP.3.0","Msxml2.XMLHTTP","Microsoft.XMLHTTP"];
for(var i=0,len=version.length; i
表中username字段
$sql = "select * from user where username ='$username'";
// echo $sql;
$res = mysql_query($sql);
$result = mysql_num_rows($res);
// var_dump($resu);die;
if($result>0){
echo "该用户已存在,请从新选择用户名~~~".$username;
}
else{
echo "恭喜你,可以注册".$username; }
}else{
echo "用户名不能为空";
}
mysql_close();