我想用ajax上传一个文件这是我的代码PHP,HTML:j查询:$(function(){$('#uploadbtn').click(function(){varfilename=$('#choosefilebtn').val();alert(filename);$.ajax({type:"POST",url:"uploadVideo.php",enctype:'multipart/form-data',data:{file:filename},success:function(){alert("DataUploaded:");}});});});当我使用typesumbmit作为上传