I'm also struggling with svg on iOS.
Several solutions exist but none of them work perfectly. If you can use png, you will save a lot of time.
If you really don't have any choice you can :
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8"/>
<meta name='viewport' content='initial-scale=1.0, maximum-scale=3.0, minimum-scale=0.5'/>
<title>SVG Displayer</title>
<style>
html, body, .content {
height: 100%;
width: 100%;
margin:0;
padding:0;
}
</style>
</head>
<body>
<div id="content" align="center">
<img height="300" src= "data:image/svg+xml;base64,SVG_CONTENT"/></img>
</div>
<div id="END"></div>
</body>
</html>
You need to replace SVG_CONTENT with your svg file encoded in base 64.
Note that I have thousands svg coming from external sources and this solution work in most of the files but not all.