how to increase font size in UIWebView

Question

how to increase or decrease the UIWebview font size, not using scalePageToFit:NO;

Answer 1

Swift 5 Update. This is an updated answer from @BLCs suggestion.

Also fixes the double %% in his string.

func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
    let textSize = 300
    let javascript = "document.getElementsByTagName('body')[0].style.webkitTextSizeAdjust= '\(textSize)%'"
    webView.evaluateJavaScript(javascript) { (response, error) in
        print()
    }
}