如何检测浏览器支持文件 API 拖放

本文介绍了如何检测浏览器支持文件 API 拖放的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我喜欢在 div 上添加背景，仅适用于支持拖动 & 的浏览器.删除文件

I like to add a background on a div only for browsers which support drag & drop for files

虽然我不喜欢使用modernizr，只是一个单行脚本

I don't like to use modernizr though, just a one line script

推荐答案

为什么不直接从 Modernizr 复制所需的部分?

Why not just copy required parts from Modernizr?

var isEventSupported = (function() { var TAGNAMES = { 'select': 'input', 'change': 'input', 'submit': 'form', 'reset': 'form', 'error': 'img', 'load': 'img', 'abort': 'img' }; function isEventSupported( eventName, element ) { element = element || document.createElement(TAGNAMES[eventName] || 'div'); eventName = 'on' + eventName; // When using `setAttribute`, IE skips "unload", WebKit skips "unload" and "resize", whereas `in` "catches" those var isSupported = eventName in element; if ( !isSupported ) { // If it has no `setAttribute` (i.e. doesn't implement Node interface), try generic element if ( !element.setAttribute ) { element = document.createElement('div'); } if ( element.setAttribute && element.removeAttribute ) { element.setAttribute(eventName, ''); isSupported = typeof element[eventName] == 'function'; // If property was created, "remove it" (by setting value to `undefined`) if ( typeof element[eventName] != 'undefined' ) { element[eventName] = undefined; } element.removeAttribute(eventName); } } element = null; return isSupported; } return isEventSupported; })();

用法:

if (isEventSupported('dragstart') && isEventSupported('drop')) { ... }

对于文件 API:

var isFileAPIEnabled = function() { return !!window.FileReader; };