You should not be using an Iframe. Apps will be rejected by apps stores if you try to do this. Use the inappbrowser for this.
In the case of @ankushagg93 app, the viewport units are to blame here. You really should avoid using them as they’re problematic.
Switching to:
.full-iframe {
position:absolute;
top: 0;
bottom:0;
left:0;
width: 100%;
}
Fixes your issue.
Really again, I cannot stress this point enough.
Using an iframe will get you app rejected by the app store and is not recommended