SyntaxError: missing ; after for-loop initializer

$.ajax({url: "<%=request.getContextPath()%>/student/timeByDate.html",method: "post",data: "date=" + $(obj).text().trim(),success: function (json) {console.log(json);for(int j=0;j<json.length;j++){  //定义类型时写成了int ，应该是varconsole.log(json[j]);}}})