錯誤提示Failed to execute 'toDataURL' on 'HTMLCanvasElement': Tainted canvases may not be exported.

導出功能直接寫在了index.html中，對應https://openlayers.org/en/latest/examples/export-pdf.html 問題：錯誤提示Failed to execute 'toDataURL' on 'HTMLCanvasElement': Tainted canvases may not be exported. canvas繪製圖片，因爲瀏覽器的安全考

>>阅读原文<<