Was able to get the datepicker to open with this code:

{name:'effDT',index:'effDT', sorttype:”date”, width:40, editable:true,

editoptions: {size: 10, maxlengh: 10,dataInit:function(element)

{$(element).datepicker()}}},

I was then getting 'URL not set' error, so I added this code to the grid definition:

editurl:'url',

cellsubmit:'clientArray',