限制文件上传的大小和尺寸

function verificationPicFile(file) {
    var fileSize = 0;
    var fileMaxSize = 1024;//1M
    var filePath = file.value;
    if(filePath){
        fileSize =file.files[0].size;
        var size = fileSize / 1024;
        if (size > fileMaxSize) {
            alert("文件大小不能大于1M！");
            file.value = "";
            return false;
        }else if (size <= 0) {
            alert("文件大小不能为0M！");
            file.value = "";
            return false;
        }
    }else{
        return false;
    }
 }

function verificationPicFile(file) {
    var filePath = file.value;
    if(filePath){
        //读取图片数据
        var filePic = file.files[0];
        var reader = new FileReader();
        reader.onload = function (e) {
            var data = e.target.result;
            //加载图片获取图片真实宽度和高度
            var image = new Image();
            image.onload=function(){
                var width = image.width;
                var height = image.height;
                if (width == 720 | height == 1280){
                    alert("文件尺寸符合！");
                }else {
                    alert("文件尺寸应为：720*1280！");
                    file.value = "";
                    return false;
                }
            };
            image.src= data;
        };
        reader.readAsDataURL(filePic);
    }else{
        return false;
    }
}