use javascript to download whole webpage code example
Example: javascript download current html page
// in the current page, download the html source
var hiddenElement = document.createElement('a');
hiddenElement.href = 'data:attachment/text,' + encodeURI(document.documentElement.outerHTML);
hiddenElement.target = '_blank';
hiddenElement.download = 'myFile.txt';
hiddenElement.click();