cefsharp cannot play audio by javascript

I am writing a dictionary program using CefSharp by C#. When the dictionary page(i.e.[Longman-love][1]) is loaded I want it could play its pronounce automatically(by clicking the pronouce icon using JavaScript). Here are related codes: C# part: JavaScript part(I copyed it from web and added some ‘alert’s for debugging the program): The last alert sentence alert(‘will play’); showed but I could not hear anything. However,when I clicked the audio icon directly in the CefSharp browser, it could play the pronounce. How could I fix this problem? I am not a native English speaker, I hope you can understand me. Many thanks!

CEFSharp Dropdown (combobox, select) open down past the edge of the browser and are clipped

Using CefSharp with WPF. I have several select elements in my pages and some of them are near the bottom of the browser. When the selects open, they open down instead of up so that user can select …