img 加载网络图片失败 显示默认图片的方法

String imgUrl = "javascript:this.src=\'http://172.21.96.31:88/k/default.jpg\'";
digest += "<img src='" + thumbnail + "' width='85px' height='70px' onerror=\""+imgUrl+"\">";

var imgPath = "javascript:this.src=\'http://172.21.96.31:88/k/default.jpg\'";
_digest += '<div style="width:85px;height:70px;padding-left:0px;">';
_digest += '<img src="' + streamuri + '/keyframes/' + mmoId + '/char.JPG" onerror="'+imgPath+'" width="85px" height="70px">';
_digest += '</div>';