replace you onmouseover="return get();" with following
onmouseover='<%# "return get(" + Eval("code") + ");" %>'
and in java script get function get code as argument like following
function get(strcode){
// pass this strcode in you ajax parameter
$.ajax({
type: "POST",
url: "Default.aspx/MyMethod",
data: "{'Code':'" + strcode + "'}",
contentType: "application/json; charset=utf-8",
dataType: "json",
success: function(result) {
}
});
}