Use the height and width attributes to specify the size of the iframe.
The height and width are specified in pixels by default:
Example
<iframe src="/html/computer.htm" height="200" width="300" title="Iframe Example"></iframe>
Or you can add the style attribute and use the CSS height and width properties:
Example
<iframe src="/html/computer.htm" style="height:200px;width:300px;" title="Iframe Example"></iframe>
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