ajax如何 实现 文件上传
程序说明
使用说明
实例化时，第一个必要参数是file控件对象：
new QuickUpload(file);
第二个可选参数用来设置系统的默认属性，包括
属性: 默认值//说明
parameter: {},//参数对象
action: "",//设置action
timeout: 0,//设置超时(秒为单位)
onReady: function(){},//上传准备时执行
onFinish: function(){},//上传完成时执行
onStop: function(){},//上传停止时执行
onTimeout: function(){}//上传超时时执行
还提供了以下方法：
upload：执行上传操作；
stop：停止上传操作；
dispose：销毁程序。
var QuickUpload = function(file, options) {
this.file = $$(file);
this._sending = false;//是否正在上传
this._timer = null;//定时器
this._iframe = null;//iframe对象
this._form = null;//form对象
this._inputs = {};//input对象
this._fFINISH = null;//完成执行函数
$$.extend(this, this._setOptions(options));
};
QuickUpload._counter = 1;
QuickUpload.prototype = {
//设置默认属性
_setOptions: function(options) {
this.options = {//默认值
action: "",//设置action
timeout: 0,//设置超时(秒为单位)
parameter: {},//参数对象
onReady: function(){},//上传准备时执行
onFinish: function(){},//上传完成时执行
onStop: function(){},//上传停止时执行
onTimeout: function(){}//上传超时时执行
};
return $$.extend(this.options, options || {});
},
//上传文件
upload: function() {
//停止上一次上传
this.stop();
//没有文件返回
if ( !this.file || !this.file.value ) return;
//可能在onReady中修改相关属性所以放前面
this.onReady();
//设置iframe,form和表单控件
this._setIframe();
this._setForm();
this._setInput();
//设置超时
if ( this.timeout > 0 ) {
this._timer = setTimeout( $$F.bind(this._timeout, this), this.timeout * 1000 );
}
//开始上传
this._form.submit();
this._sending = true;
},
//设置iframe
_setIframe: function() {
if ( !this._iframe ) {
//创建iframe
var iframename = "QUICKUPLOAD_" + QuickUpload._counter++,
iframe = document.createElement( $$B.ie ? "<iframe name=\"" + iframename + "\">" : "iframe");
iframe.name = iframename;
iframe.style.display = "none";
//记录完成程序方便移除
var finish = this._fFINISH = $$F.bind(this._finish, this);
//iframe加载完后执行完成程序
if ( $$B.ie ) {
iframe.attachEvent( "onload", finish );
} else {
iframe.onload = $$B.opera ? function(){ this.onload = finish; } : finish;
}
//插入body
var body = document.body; body.insertBefore( iframe, body.childNodes[0] );
this._iframe = iframe;
}
},
//设置form
_setForm: function() {
if ( !this._form ) {
var form = document.createElement('form'), file = this.file;
//设置属性
$$.extend(form, {
target: this._iframe.name, method: "post", encoding: "multipart/form-data"
});
//设置样式
$$D.setStyle(form, {
padding: 0, margin: 0, border: 0,
backgroundColor: "transparent", display: "inline"
});
//提交前去掉form
file.form && $$E.addEvent(file.form, "submit", $$F.bind(this.dispose, this));
//插入form
file.parentNode.insertBefore(form, file).appendChild(file);
this._form = form;
}
//action可能会修改
this._form.action = this.action;
},
//设置input
_setInput: function() {
var form = this._form, oldInputs = this._inputs, newInputs = {}, name;
//设置input
for ( name in this.parameter ) {
var input = form[name];
if ( !input ) {
//如果没有对应input新建一个
input = document.createElement("input");
input.name = name; input.type = "hidden";
form.appendChild(input);
}
input.value = this.parameter[name];
//记录当前input
newInputs[name] = input;
//删除已有记录
delete oldInputs[name];
}
//移除无用input
for ( name in oldInputs ) { form.removeChild( oldInputs[name] ); }
//保存当前input
this._inputs = newInputs;
},
//停止上传
stop: function() {
if ( this._sending ) {
this._sending = false;
clearTimeout(this._timer);
//重置iframe
if ( $$B.opera ) {//opera通过设置src会有问题
this._removeIframe();
} else {
this._iframe.src = "";
}
this.onStop();
}
},
//销毁程序
dispose: function() {
this._sending = false;
clearTimeout(this._timer);
//清除iframe
if ( $$B.firefox ) {
setTimeout($$F.bind(this._removeIframe, this), 0);
} else {
this._removeIframe();
}
//清除form
this._removeForm();
//清除dom关联
this._inputs = this._fFINISH = this.file = null;
},
//清除iframe
_removeIframe: function() {
if ( this._iframe ) {
var iframe = this._iframe;
$$B.ie ? iframe.detachEvent( "onload", this._fFINISH ) : ( iframe.onload = null );
document.body.removeChild(iframe); this._iframe = null;
}
},
//清除form
_removeForm: function() {
if ( this._form ) {
var form = this._form, parent = form.parentNode;
if ( parent ) {
parent.insertBefore(this.file, form); parent.removeChild(form);
}
this._form = this._inputs = null;
}
},
//超时函数
_timeout: function() {
if ( this._sending ) { this._sending = false; this.stop(); this.onTimeout(); }
},
//完成函数
_finish: function() {
if ( this._sending ) { this._sending = false; this.onFinish(this._iframe); }
}
}
2、这个是要看你服务器端用的是什么语言了，PHP、Java还是ASP用法都大同小异
3、前不久刚刚写了个Demo是用PHP实现的你看一下原理，是不是你想要的呢演示地址:www.erdangjiade.com/js/513.html
前端代码为：
<form class="imageform" method="post" enctype="multipart/form-data" action="upload.php"> <div class="up_status" style="display:none"><img src="loader.gif" alt="uploading"/></div> <div class="btn up_btn"> <span>添加图片</span> <input class="photoimg" type="file" name="photoimg"> </div> </form> <div class="preview_img"></div>Jquery代码：
<link rel="stylesheet" type="text/css" href="css/style.css" /> <script type="text/javascript" src="<script type="text/javascript" src="jquery.wallform.js"></script>$("body").on("change", ".photoimg", function() { var obj = $(this); var imageForm = obj.parents(".imageform"); var preview_img = imageForm.next(".preview_img"); var btn = imageForm.find(".up_btn"); imageForm.ajaxForm({ target: preview_img, beforeSubmit: function() { imageForm.next("div.preview_img").html(""); preview_img.hide(); btn.hide(); }, success: function() { preview_img.show(); btn.show(); }, error: function() { btn.show(); preview_img.hide(); } }).submit(); });PHP代码为：
PHP上传 upload.phpif (isset($_POST) and $_SERVER['REQUEST_METHOD'] == "POST") { $name = $_FILES['photoimg']['name']; $size = $_FILES['photoimg']['size']; if (empty($name)) { echo '请选择要上传的图片'; exit; } $ext = extend($name); if (!in_array($ext, $extArr)) { echo '图片格式错误！'; exit; } if ($size > (1000 * 1024)) { echo '图片大小不能超过1M'; exit; } $image_name = time() . rand(100, 999) . "." . $ext; $tmp = $_FILES['photoimg']['tmp_name']; if (move_uploaded_file($tmp, $path . $image_name)) { echo '<img src="' . $path . $image_name . '" class="preview">'; } else { echo '上传出错了！'; } exit; }效果图：
