无刷新文件上传是一个常见而又有点复杂的问题，常见的解决方案是构造 iframe 方式实现。
在 HTML5 中提供了一个 FormData 对象 API，通过 FormData 可以方便地构造一个表单请求，并通过 XMLHttpRequest 来发送。通过 FormData 对象发送文件也是可以的，如此则无刷新上传就变的非常简单了。
那么 FormData 怎么使用呢？下面脚本之家对此进行简单的介绍。
1. 构造 FormData 对象
想得到一个FormData对象，很简单：
var fd = new FormData();
FormData 对象只提供了一个方法 append ，用于向对象中添加表单请求参数。
在当前主流浏览器中，可通过如下两种方式获取或修改FormData。
方法一：创建一个空的FormData对象，然后再用append方法逐个添加键值对。示例：
var fd = new FormData();
fd.append("name", "脚本之家");
fd.append("blog", "http://php.net");
fd.append("file", document.getElementById("file"));
这种方法可以不需要 HTML 的表单对象存在。
方法二：取得form元素对象，将它作为参数传入FormData对象中。示例：
var formobj = document.getElementById("form");
var fd = new FormData(formobj);
当然，这里还可以使用 append 方法继续向 fd 中添加其他参数。
2. FormData 发送请求
得到 FormData 对象了，如何发送请求呢？ FormData 对象主要用于增强型的 XMLHttpRequest 对象的 send 方法中。参考如下示例：
var xhr = new XMLHttpRequest();
xhr.open("POST" ,"http://php.net" , true);
xhr.send(fd);
xhr.onload = function(e) {
if (this.status == 200) {
alert(this.responseText);
}
};
3. jquery 中使用 FormData
在 jQuery 的 ajax 方法中，也可使用 FormData 方式实现无刷新上传。但要注意参数的设置，参考如下：
$.ajax({
url: "http://php.net",
type: 'POST',
data: fd,
/**
*必须false才会自动加上正确的Content-Type
*/
contentType:false,
/**
* 必须false才会避开jQuery对 formdata 的默认处理
* XMLHttpRequest会对 formdata 进行正确的处理
*/
processData:false
}).done(function(result){
console.log(result);
}).fail(function(err){
console.log(err);
});
4. 一个完整的示例（包含PHP处理示例）：
<?php
//php 接收表单提交信息并打印
if( isset( $_REQUEST['do']) ){
var_dump($_REQUEST);
var_dump($_FILES);
die();
}
?>
<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8">
<title>FormData Test - php.net</title>
<script src="http://libs.baidu.com/jquery/2.0.0/jquery.min.js"></script>
</head>
<body>
<form id="form">
<input type="file" name="file" id="file" />
<input type="text" name="name" id="" value="脚本之家" />
<input type="text" name="blog" id="" value="http://php.net" />
<input type="submit" name="do" id="do" value="submit" />
</form>
<script>
$("form").submit(function(e){
e.preventDefault();
//空对象然后添加
var fd = new FormData();
fd.append("name", "脚本之家");
fd.append("blog", "http://php.net");
fd.append("file", document.getElementById("file"));
//fd.append("file", $(":file")[0].files[0]); //jQuery 方式
fd.append("do", "submit");
//通过表单对象创建 FormData
var fd = new FormData(document.getElementById("form"));
//var fd = new FormData($("form:eq(0)")[0]); //jquery 方式
//XMLHttpRequest 原生方式发送请求
var xhr = new XMLHttpRequest();
xhr.open("POST" ,"" , true);
xhr.send(fd);
xhr.onload = function(e) {
if (this.status == 200) {
alert(this.responseText);
};
};
return;
//jQuery 方式发送请求
$.ajax({
type:"post",
//url:"",
data: fd,
processData: false,
contentType: false
}).done(function(res){
console.log(res);
});
return false;
});
</script>
</body>
</html>
PHP Dependency Injection Container: A Quick StartMay 13, 2025 am 12:11 AMAPHPDependencyInjectionContainerisatoolthatmanagesclassdependencies,enhancingcodemodularity,testability,andmaintainability.Itactsasacentralhubforcreatingandinjectingdependencies,thusreducingtightcouplingandeasingunittesting.
Dependency Injection vs. Service Locator in PHPMay 13, 2025 am 12:10 AMSelect DependencyInjection (DI) for large applications, ServiceLocator is suitable for small projects or prototypes. 1) DI improves the testability and modularity of the code through constructor injection. 2) ServiceLocator obtains services through center registration, which is convenient but may lead to an increase in code coupling.
PHP performance optimization strategies.May 13, 2025 am 12:06 AMPHPapplicationscanbeoptimizedforspeedandefficiencyby:1)enablingopcacheinphp.ini,2)usingpreparedstatementswithPDOfordatabasequeries,3)replacingloopswitharray_filterandarray_mapfordataprocessing,4)configuringNginxasareverseproxy,5)implementingcachingwi
PHP Email Validation: Ensuring Emails Are Sent CorrectlyMay 13, 2025 am 12:06 AMPHPemailvalidationinvolvesthreesteps:1)Formatvalidationusingregularexpressionstochecktheemailformat;2)DNSvalidationtoensurethedomainhasavalidMXrecord;3)SMTPvalidation,themostthoroughmethod,whichchecksifthemailboxexistsbyconnectingtotheSMTPserver.Impl
How to make PHP applications fasterMay 12, 2025 am 12:12 AMTomakePHPapplicationsfaster,followthesesteps:1)UseOpcodeCachinglikeOPcachetostoreprecompiledscriptbytecode.2)MinimizeDatabaseQueriesbyusingquerycachingandefficientindexing.3)LeveragePHP7 Featuresforbettercodeefficiency.4)ImplementCachingStrategiessuc
PHP Performance Optimization Checklist: Improve Speed NowMay 12, 2025 am 12:07 AMToimprovePHPapplicationspeed,followthesesteps:1)EnableopcodecachingwithAPCutoreducescriptexecutiontime.2)ImplementdatabasequerycachingusingPDOtominimizedatabasehits.3)UseHTTP/2tomultiplexrequestsandreduceconnectionoverhead.4)Limitsessionusagebyclosin
PHP Dependency Injection: Improve Code TestabilityMay 12, 2025 am 12:03 AMDependency injection (DI) significantly improves the testability of PHP code by explicitly transitive dependencies. 1) DI decoupling classes and specific implementations make testing and maintenance more flexible. 2) Among the three types, the constructor injects explicit expression dependencies to keep the state consistent. 3) Use DI containers to manage complex dependencies to improve code quality and development efficiency.
PHP Performance Optimization: Database Query OptimizationMay 12, 2025 am 12:02 AMDatabasequeryoptimizationinPHPinvolvesseveralstrategiestoenhanceperformance.1)Selectonlynecessarycolumnstoreducedatatransfer.2)Useindexingtospeedupdataretrieval.3)Implementquerycachingtostoreresultsoffrequentqueries.4)Utilizepreparedstatementsforeffi
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Dreamweaver CS6
Visual web development tools
WebStorm Mac version
Useful JavaScript development tools
PhpStorm Mac version
The latest (2018.2.1) professional PHP integrated development tool
mPDF
mPDF is a PHP library that can generate PDF files from UTF-8 encoded HTML. The original author, Ian Back, wrote mPDF to output PDF files "on the fly" from his website and handle different languages. It is slower than original scripts like HTML2FPDF and produces larger files when using Unicode fonts, but supports CSS styles etc. and has a lot of enhancements. Supports almost all languages, including RTL (Arabic and Hebrew) and CJK (Chinese, Japanese and Korean). Supports nested block-level elements (such as P, DIV),
