如何检测浏览器支持文件API拖动下拉 [英] How to detect browser support File API drag n drop
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问题描述
我喜欢在div上添加一个背景,仅用于支持拖放功能的浏览器。下载文件
我不喜欢使用modernizr,只是一行脚本
解决方案
为什么不从Modernizr复制所需的部件?
var isEventSupported =(function(){
var TAGNAMES = {
'select':'input','change':'input',
'submit':'form','reset' ,
'error':'img','load':'img','abort':'img'
};
函数isEventSupported(eventName,element){
element = element || document.createElement(TAGNAMES [eventName] ||'div');
eventName ='on'+ eventName;
//当使用setAttribute时,IE跳过卸载,WebKit跳过卸载和调整大小,而incatch这些
var isSupported =元素中的eventName;
if (!isSupported){
//如果没有`setAtt ribute(即不实现Node接口),尝试通用元素
if(!element.setAttribute){
element = document.createElement('div');
}
if(element.setAttribute&& element.removeAttribute){
element.setAttribute(eventName,'');
isSupported = typeof element [eventName] =='function';
//如果属性被创建,删除它(通过将值设置为'undefined`)
if(typeof element [eventName]!='undefined'){
element [eventName] = undefined;
}
element.removeAttribute(eventName);
}
}
元素= null;
return isSupported;
}
return isEventSupported;
})();
用法:
code> if(isEventSupported('dragstart')&& isEventSupported('drop')){
...
}
pre>
对于文件API:
var isFileAPIEnabled = function ){
return !! window.FileReader;
};
I like to add a background on a div only for browsers which support drag & drop for files
I don't like to use modernizr though, just a one line script
解决方案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; })();
Usage:
if (isEventSupported('dragstart') && isEventSupported('drop')) { ... }
And for File API:
var isFileAPIEnabled = function() { return !!window.FileReader; };
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