AJAX-----09iframe模拟ajax文件上传效果原理1

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <script src="jq183.js"></script>
    <script>
        function ajaxup(){
            var ifname = 'up'+Math.random();
            $("<iframe name='"+ ifname +"'></iframe>").appendTo($('body'));
            $('form:first').attr('target',ifname);
            return false;
        }
    </script>
</head>
<body>
    <form action="9.php" method="post" enctype="multipart/form-data" onsubmit="return ajaxup();">
        <input type="file" name="pic"> <br> <br>
        <input type="submit" value="GO">
    </form>
</body>
</html>

我们众所周知后端error如果等于相当于上传成功，所以暂时用一个临时数据来模拟下意思

<?php
    if(empty($_FILES)){
        exit('No file');
    }

    echo $_FILES['pic']['error'] == 0 ? 'success':'error';