Here the following method does that.the html file with
location is passed to the method.after getting the
content of the html file in StringBuilder,the method
returns it.then you can write back the content to the
html file again.

public static System.Text.StringBuilder ReadHtmlFile(string htmlFileNameWithPath)
{
System.Text.StringBuilder storeContent = new System.Text.StringBuilder();

try
{
using (System.IO.StreamReader htmlReader = new System.IO.StreamReader(htmlFileNameWithPath))
{
string lineStr;
while ((lineStr = htmlReader.ReadLine()) != null)
{
storeContent.Append(lineStr);
}
}
}
catch (Exception objError)
{
throw objError;
}

return storeContent;
}

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