Apex iframe attribute is not working in vf page

Question

apex iframe is not showing anything. I am trying to open a standard dashboard in vf page using following code:

<apex:iframe id="iframeID" src="/dashboardId"/>

Answer 1

Assuming that dashboardId is the property in the controller of your VF page in which the URL to your dashboard is stored, you should use VF binding to output the value of the property into the component:

<apex:iframe id="iframeID" src="/{!dashboardId}" />

If you're just trying to reference the dashboard with the dashboard ID hardcoded in the VF code, then make sure to append isdtp=nv to URL as query string params, e.g.:

<apex:iframe id="iframeID" src="/01Z30000000ntSy?isdtp=nv" />

Explanation on isdtp query string options:

isdtp=vw : The page will be rendered without the tabs and sidebar.
isdtp=nv : The page will be rendered without the tabs and sidebar, and will accommodate all the buttons in a list view