Introduction to functions for filtering Html

//过滤Html的函数
public string checkStr(string html)
{
    System.Text.RegularExpressions.Regex regex1 =
        new System.Text.RegularExpressions.Regex(@"<script[\s\S]+</script *>",
            System.Text.RegularExpressions.RegexOptions.IgnoreCase);
    System.Text.RegularExpressions.Regex regex2 =
        new System.Text.RegularExpressions.Regex(@" href *= *[\s\S]*script *:",
            System.Text.RegularExpressions.RegexOptions.IgnoreCase);
    System.Text.RegularExpressions.Regex regex3 =
        new System.Text.RegularExpressions.Regex(@" no[\s\S]*=",
            System.Text.RegularExpressions.RegexOptions.IgnoreCase);
    System.Text.RegularExpressions.Regex regex4 =
        new System.Text.RegularExpressions.Regex(@"<iframe[\s\S]+</iframe *>",
            System.Text.RegularExpressions.RegexOptions.IgnoreCase);
    System.Text.RegularExpressions.Regex regex5 =
        new System.Text.RegularExpressions.Regex(@"<frameset[\s\S]+</frameset *>",
            System.Text.RegularExpressions.RegexOptions.IgnoreCase);
    System.Text.RegularExpressions.Regex regex6 =
                new System.Text.RegularExpressions.Regex(@"\<img[^\>]+\>",
                    System.Text.RegularExpressions.RegexOptions.IgnoreCase);
    System.Text.RegularExpressions.Regex regex7 =
        new System.Text.RegularExpressions.Regex(@"</p>",
            System.Text.RegularExpressions.RegexOptions.IgnoreCase);
    System.Text.RegularExpressions.Regex regex8 =
        new System.Text.RegularExpressions.Regex(@"<p>",
            System.Text.RegularExpressions.RegexOptions.IgnoreCase);
    System.Text.RegularExpressions.Regex regex9 =
        new System.Text.RegularExpressions.Regex(@"<[^>]*>",
            System.Text.RegularExpressions.RegexOptions.IgnoreCase);
    html = regex1.Replace(html, ""); //过滤<script></script>标记 
    html = regex2.Replace(html, ""); //过滤href=javascript: (<A>) 属性 
    html = regex3.Replace(html, " _disibledevent="); //过滤其它控件的on...事件 
    html = regex4.Replace(html, ""); //过滤iframe
    html = regex5.Replace(html, ""); //过滤frameset 
    html = regex6.Replace(html, ""); //过滤frameset
    html = regex7.Replace(html, ""); //过滤frameset
    html = regex8.Replace(html, ""); //过滤frameset
    html = regex9.Replace(html, "");
    html = html.Replace(" ", "");
    html = html.Replace("</strong>", "");
    html = html.Replace("<strong>", "");
    return html;
}