前端JS常用方法

// 获取本地文件URL
function getObjectURL(file) {
	var url = null;
	if (window.createObjcectURL != undefined) {
	    url = window.createOjcectURL(file);
	} else if (window.URL != undefined) {
	    url = window.URL.createObjectURL(file);
	} else if (window.webkitURL != undefined) {
	    url = window.webkitURL.createObjectURL(file);
	}
	return url;
}

// 将base64转换为文件
function dataURLtoFile(dataurl, filename) {
	var arr = dataurl.split(','), mime = arr[0].match(/:(.*?);/)[1],
	bstr = atob(arr[1]), n = bstr.length, u8arr = new Uint8Array(n);
	while(n--){
		u8arr[n] = bstr.charCodeAt(n);
	}
	return new File([u8arr], filename, {type:mime});
}