# # Javascript evaluation

Evaluate Javascript from Python code.

    import webview

    def evaluate_js(window):
        result = window.evaluate_js(
            r"""
            var h1 = document.createElement('h1')
            var text = document.createTextNode('Hello pywebview')
            h1.appendChild(text)
            document.body.appendChild(h1)

            document.body.style.backgroundColor = '#212121'
            document.body.style.color = '#f2f2f2'

            // Return user agent
            'User agent:\n' + navigator.userAgent;
            """
        )

        print(result)

    if __name__ == '__main__':
        window = webview.create_window('Run custom JavaScript')
        webview.start(evaluate_js, window)