jQuery Grid Plugin - jqGrid

Hi,

I have the following colModel:

[

{"name":"Id","index":"1","formatter":"text"},
{"name":"Name","index":"2","formatter":"text"},
{"name":"BillingCity","index":"3","formatter":"text"},
{"name":"BillingPostalCode","index":"4","formatter":"text"},
{"name":"BillingState","index":"5","formatter":"text"},
{"name":"Type","index":"6","formatter":"text"},
{"name":"Industry","index":"7","formatter":"text"}

]

 

I am trying to display the undefined values into blank text and I already have the following function in place:

function text (cellvalue, options, rowObject) {
 if (jQuery.type(cellvalue) === "undefined") {
 alert("Hello!");
 return "";
 } else {
 alert("World!");
 }
 }

For some reason, the undefined values are still displaying as "undefined" on the grid. I was wondering what I might have done wrong for it not to work?