How to put a Partial View into a div in JavaScript (with jQuery)

I have ,MyPartialView.cshtml':

<div id="partialDiv">some content</div> 

an 'index.cshtml':

<div id="mainDiv"> </div>

and an 'index.js'.

The 'index.js' should do sth like:

$('mainDiv').html($('#partialDiv'))

to put the partial view into the main div.

(writing @<text> <div> @Html.Partial("MyPartialView")</div></text>) in my .cshtml works, but I need to change the content dynamically. Therefore, I thought maybe there is an equivalent in JavaScript for 'Html.Partial'

(Or is there another way to get a Partial View without an AJAX Call)

@Html.Partial("MyPartialView") used only to render single partial view file (also with @Html.RenderPartial()). You can use AJAX to call controller action which returns partial view:

AJAX Request

$.ajax({
    type: 'GET',
    url: '@Url.Action("ActionName", "ControllerName")',
    // other settings
    success: function (result) {
        $('mainDiv').html(result);
    }
});

Controller Action

[HttpGet]
public ActionResult ActionName()
{
    // do something
    return PartialView("MyPartialView");
}

Note that there's no equivalent of calling partial view in JS, because you need to make request to server which can't be simply handled by standard JS functions.