How to update the CSS of an iFrame with pure javascript not with jquery

Question

I want to apply the custom CSS for the below iframe,

<iframe width="100%" class="freshwidget-embedded-form" id="freshwidget-embedded-form" src="http://customerservice.millers.com.au/widgets/feedback_widget/new?&amp;widgetType=embedded&amp;screenshot=no" scrolling="no" height="550px" frameborder="0"></iframe>

Please let me know how will i be able to modify the CSS of any class/element within the iFrame via JavaScript.

Answer 1

I think the question is not clear enough but I am going ahead and assume that you want to change the style or an attribute such as "src" using pure javascript,

So to change a style you have to grab the id or class then change the style, in your case it will be.

document.getElementById(freshwidget-embedded-form).style.width = "new_width"

or if you want to change the source it will be like

document.getElementById(freshwidget-embedded-form).src = "new src for the media"