js实现拖拽文件上传

//拖拽文件刚到目标上$$('#app-form').on('dragenter', function () {console.log("dragenter");});//拖拽在目标上，一直执行$$('#app-form').on('dragover', function () {console.log("dragover");$$('#app-form').css("background","green");return false;});//拖拽时离开目标$$('#app-form').on("dragleave", function () {console.log("dragleave");$$('#app-form').css("background","none");});//拖拽到目标并释放$$('#app-form').on("drop", function (ev) {console.log("drop");$$('#app-form').css("background","none");var fs = ev.dataTransfer.files;uploadFile(fs);return false;});