利用formdata异步上传图片并预览图片

<img src="" style="width: 120px;margin-bottom: 5px" id="previewimg0"><form action="" enctype="multipart/form-data" id="form0"> ??<input type="file" ?name="file" id="file0" onChange="preview(this,0)" style="width: 70px;margin-left: 25px"></form>

function preview(obj,id){ ??????var img = document.getElementById("previewimg"+id); ??????img.src = window.URL.createObjectURL(obj.files[0]); ??????var data = new FormData($(‘#form‘+id)[0]); ??????$.ajax({ ??????????url: ‘uploadoption.php‘, ??????????type: ‘POST‘, ??????????data: data, ??????????dataType: ‘JSON‘, ??????????cache: false, ??????????processData: false, ??????????contentType: false ??????}).done(function(ret){ ??????????if(ret[‘isSuccess‘]){ ??????????????img.src = window.URL.createObjectURL(obj.files[0]); ??????????}else{ ??????????????alert(‘提交失敗‘); ??????????} ??????}); ??}

 1 <?php 2 $file = $_FILES[‘file‘];//得到传输的数据 3 $Name = $file[‘name‘];//得到文件名称 4 ?5 $type = strtolower(substr($Name,strrpos($Name,‘.‘)+1));//得到文件类型。转为小写 6 $allow_type = array(‘jpg‘,‘jpeg‘,‘gif‘,‘png‘);//定义允许上传的类型 7 //判断文件类型是否允许上传 8 if(!in_array($type,$allow_type)){ 9 ???//如果不允许，直接停止10 ???return;11 }12 //判读是否通过http post上传13 if(!is_uploaded_file($file[‘tmp_name‘])){14 ???return;15 }16 $upload_path = "image/";//上传文件的存放路径17 //开始移动文件到相应的文件夹18 if(move_uploaded_file($file[‘tmp_name‘],$upload_path.$file[‘name‘])){19 ???$response[‘isSuccess‘] = true;20 ???$response[‘photo‘] = $upload_path.$file[‘name‘];21 }else{22 ???$response[‘isSuccess‘] = false;23 }24 25 //$picture = $upload_path.$file[‘name‘];26 echo json_encode($response);