上传图片预览

jQuery.fn.extend({
       previewInputImage: function($inputElement, fileIndex){
           if(typeof(fileIndex) == 'undefined'){
               fileIndex = 0;
           }
           var $imageElement = $(this);
           var input = $inputElement.get(0);
           if (input.files && input.files[fileIndex]) {
               var reader = new FileReader();
         reader.onload = function (e) {
           $imageElement.attr('src', e.target.result);
         }
         reader.readAsDataURL(input.files[fileIndex]);
           }
           return $(this);
       }
   });
   $('.brand-logo .btn-upload input[type=file]').on('change', function(){
        $('.brand-logo .img-thumbnail').previewInputImage($(this));
   });