YN标记：
formatter : function(c1, row,index) {
var a = "";
if(c1 == "Y"){
a = a + "<div style = "background-color:00FF"> 正确";
}else if(c2 == "N"){
a = a + "<div style = \"background-color:FF0000\"> 错误</div>";
}else{
a;
}
NULL和非NULL判断 并且悬浮显示单元格内容：
//判断是否为空，若不为空显示答案并且鼠标悬浮显示
formatter : function(value, row, index) {
var a = "";
if(value == null){
}else{
return "" + value + "";
}
}
}