C#实现过滤HTML代码的函数

public string checkStr(string html) 
{ 
System.Text.RegularExpressions.Regex regex1 = 

      new System.Text.RegularExpressions.Regex(@"<script[sS]+</script *>", 

      System.Text.RegularExpressions.RegexOptions.IgnoreCase); 
System.Text.RegularExpressions.Regex regex2 = 

      new System.Text.RegularExpressions.Regex(@" href *= *[sS]*script *:", 

      System.Text.RegularExpressions.RegexOptions.IgnoreCase); 
System.Text.RegularExpressions.Regex regex3 = 

      new System.Text.RegularExpressions.Regex(@" no[sS]*=", 

      System.Text.RegularExpressions.RegexOptions.IgnoreCase); 
System.Text.RegularExpressions.Regex regex4 = 

      new System.Text.RegularExpressions.Regex(@"<iframe[sS]+</iframe *>", 

      System.Text.RegularExpressions.RegexOptions.IgnoreCase); 
System.Text.RegularExpressions.Regex regex5 = 

      new System.Text.RegularExpressions.Regex(@"<frameset[sS]+</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; 
}