控制图片上传宽高

var _URL = window.URL || window.webkitURL;
var file, img;
if((file = $("#picFile")[0].files[0])) {
img = new Image();
img.onload = function() {
//如果是首页banner图片,750*180
if($("#addType").val() == 2) {
if(this.width != 750 || this.height != 180) {
$.messager.alert('错误', '弹窗图片宽高必须是750px*180px', 'error');
} else {
ajaxAddForm();
}
}
if($("#addType").val() == 5) {
if(this.width != 750 || this.height != 300) {
$.messager.alert('错误', '弹窗图片宽高必须是750px*300px', 'error');
} else {
ajaxAddForm();
}
}
}
img.src = _URL.createObjectURL(file);

};

//获取input图片宽高和大小

function getImageWidthAndHeight(id, callback) {

  var _URL = window.URL || window.webkitURL;

  $("#" + id).change(function (e) {

    var file, img;

    if ((file = this.files[0])) {

      img = new Image();

      img.onload = function () {

        callback && callback({"width": this.width, "height": this.height, "filesize": file.size});

      };

      img.src = _URL.createObjectURL(file);

    }

  });

}

(function () {

  //省略其他代码

  getImageWidthAndHeight('image_file', function (obj) {

   if (obj.width != 843 || obj.height != 1038) {

    $.messager.alert('操作提示', '弹窗图片宽高必须是843*1038px');

   }

  });

})(jQuery)