I Have Problem when loading Iframe?

Question

This is my code:

$("#btnAssignVendor").on("click", function (e) {

$(".modal-body").html('<iframe width="100%" height="88%" frameborder="0" scrolling="yes" allowtransparency="true" src="@Url.Action("SearchVendor", "Job", new { id = @Model.JobID, IsModel = true })"></iframe>');

$('.modal').modal({ backdrop: 'static', keyboard: false }, 'show');

return false;

});

 

When clicking on button modal pop is open but the initial blank white page is opening. Instead of that initial i need to load loader image. May i know how to do that.

 

please help asap