//Front-end data submission
$('#submit').on("click",function (event) {
alert("hao");
$.ajax( {
type: "POST",
url: "{:url('Ruku/tianjia')}",
data: $("#form-admin-add").serialize(),
dataType: "json",
success: function(data){
alert(data);
}#%2
Try changing it to the following:
$param = $this->request->param();