A vanilla JavaScript fix (of sorts) for responsive SVGs in Safari and some other WebKit browsers.

JSfixForResponsiveSVGsInSafari.js

/*
Title: Vanilla JavaScript to fix responsive SVGs in some versions of Safari.
What it does: Stops the problem I described here: http://stackoverflow.com/q/17158717/1147859 Reference URL of the issue: http://codepen.io/benfrain/full/fhyrD

It will work on all SVGs referenced inside objects as long as given the class .emb:

<object class="emb" data="img/cup.svg" type="image/svg+xml"></object>

And also any inline SVGs.

Necassary CSS (!important should be optional)

svg {
	height: 100%!important;
	width: 100%!important;
}

Author: Ben Frain
Date: 21.6.2013
Version 0.1

Pointers on the embedded SVGs from Erik Dahlström: http://xn--dahlstrm-t4a.net/svg/html/get-embedded-svg-document-script.html from this Stack Overflow question: http://stackoverflow.com/a/8134698/1147859
*/

// wait until all the resources are loaded
window.addEventListener("load", function(){
	findSVGs();
	inlineSVGs();
},false);
window.addEventListener("resize", function(){
	findSVGs();
	inlineSVGs();
},false) ;

// fetches the document for the given embedding_element
var getSubDocument = function(embedding_element) {
	if (embedding_element.contentDocument)
	{
		return embedding_element.contentDocument;
	}
	else
	{
		var subdoc = null;
		try {
			subdoc = embedding_element.getSVGDocument();
		} catch(e) {}
		return subdoc;
	}
};

var findSVGs = function() {
	// Find all emements with a class of .emb
	var elms = document.querySelectorAll(".emb");
	// Make a loop for each
	for (var i = 0; i < elms.length; i++) {
		// Get the SVG whether content or iframe etc
		subdoc = getSubDocument(elms[i]);

		// Get the internal SVG document
		SVGdoc = subdoc.documentElement;
		// If it exists set the SVG to be width and height 100%;
		if (subdoc)
			SVGdoc.setAttribute("height", "100%");
			SVGdoc.setAttribute("width", "100%");
	}
};

var inlineSVGs = function() {
	// Find all inline elements
	var inlines = document.getElementsByTagName("svg");
	// Make a loop for each
	for (var i = 0; i < inlines.length; i++) {
		// Get the computed width of the SVG as determined by UA
		ComputedSVGWidthRaw = inlines[i].getBoundingClientRect().width.toFixed(0);
		ComputedSVGWidth = inlines[i].getBoundingClientRect().width.toFixed(0) + 'px';

		// If no height or width on SVG:
		if (!inlines[i].hasAttribute("height") || !inlines[i].hasAttribute("width")) {
			// If it has no width/height and ALSO DOES NOT have a viewBox:
			if (!inlines[i].hasAttribute("viewBox")) {
				// Then set the height to be the same as the ComputedSVGWidth
				inlines[i].setAttribute("height", ComputedSVGWidth);
				inlines[i].setAttribute("width", ComputedSVGWidth);
			}
			// If it has no width/height but DOES have a viewbox:
			else {
				// Split contents of the viewBox into an array
				viewBox = inlines[i].getAttribute("viewBox").split(/[\s,]+/);
				// With viewBox Width and Height are the last two values
				viewBoxHeight = viewBox[viewBox.length-1];
				viewBoxWidth = viewBox[viewBox.length-2];
				HeightProportionFromViewBox = (viewBoxHeight / viewBoxWidth);
				HeightfromViewBoxProportion = (ComputedSVGWidthRaw * HeightProportionFromViewBox).toFixed(0) + 'px';

				// OK, let's set this Mofo:
				inlines[i].setAttribute("width", ComputedSVGWidth);
				inlines[i].setAttribute("height", HeightfromViewBoxProportion);
			}
		}
		// At this point we have height and width
		else {
			// Get the height/width of the SVG sans units
			OriginalSVGheight = parseInt(inlines[i].getAttribute("height"), 10);
			OriginalSVGwidth = parseInt(inlines[i].getAttribute("width"), 10);

			// Get the ratios of height and width
			RatioOfHeightToWidth = (OriginalSVGheight / OriginalSVGwidth).toFixed(0);
			RatioOfWidthToHeight = (OriginalSVGwidth / OriginalSVGheight);

			// Define each width and height as value and add px to it - remove decimals to prevent rouding discrepancies
			HeightAsProportion = (RatioOfHeightToWidth * ComputedSVGWidthRaw).toFixed(0) + 'px';
			WidthAsProportion = (parseInt(HeightAsProportion, 10) * RatioOfWidthToHeight).toFixed(0) + 'px';

			inlines[i].setAttribute("width", WidthAsProportion);
			inlines[i].setAttribute("height", HeightAsProportion);
		}
	}
};