How to get scrollTop of an iframe

$('#myIframe').contents().scrollTop()

$('#myIframe').contents().scrollTop(0);

Only works with "0" as parameter

I have try to

$('#myIframe').contents().scrollTop(0);

and

 let scrollTop = document.getElementById(IFRAME_ID).contentWindow.document.body.scrollTop;

the first function work success in desktop browser. not working in mobile browser. so I use another function with scrollIntoView

$("#ButtonId").click(function() {
        var win = document.getElementById(IFRAMEID).contentWindow;
        var scrollTop = win.document.documentElement.scrollTop || win.pageYOffset || win.document.body.scrollTop;
        // scrollTop can getted
        if (scrollTop) {
            win.document.documentElement.scrollTop = 0;
            win.pageYOffset = 0; // safari
            win.document.body.scrollTop = 0;
        } else {
            win.document.body.scrollIntoView(true); // let scroll to the target view 
        }
    });

scrollIntoView() view in scrollIntoView - MDN

I know I'm late to the game here, but I was trying to figure this out for a long list on mobile. scrollTop() wasn't working for me due to cross-domain conflicts(and I didn't have access to parent window), but changing the height did:

$('#someClickableElementInIFrame').on('click', function(e){
      $("html body").animate({
      'height' : "0"
    }, {
        complete: function(){
          $("html body").css({
            'height' : "auto"
            })
          }
      })
});

Cause you using iFrame you will need to use it that way with windows "message" event

Read here for more Info

On Child View (Iframe)

window.top.postMessage(0 + '$' + 'form-iframe-top', "*");

On Parent View

   window.addEventListener("message",function(e) {
       if (e && e.data && typeof e.data == "string" && e.data != undefined) {
         var data = e.data.split("$");
             if (data.length == 2) {
               var scroll_height = data[0], iframe_id = data[1];
               if(iframe_id=="form-iframe-top"){
                   window.scrollTo(0,scroll_height);
                   return;
                  }
               }
          }
         },
        false
      );

**Note i used "*" as separator you can use anything

I have faced the same problem in my iframe. My whole website comming white iframe and scrolling not working So I used this code and it's work fine.

Step 1. put this code to your iframe

var offsettop =  120;
window.parent.postMessage({"setAnchor": offsettop}, "*");

Step 2. put this code where your call you iframe

window.addEventListener('message', function(event) {
  if(event.data['setAnchor']>0) {
    var offsetHeight =event.data['setAnchor'];
    jQuery('html, body').animate({
      scrollTop: offsetHeight
    }, 200);
  } 
})