如何在webbrowser对网页中的div添加如何在webbrowser对网页中的div添加onmouseover/onmouseout


webbrowser打开某网站网页，然后通过循环找到div的rowIndex="0"并且是“回复”按钮的那行，添加onmouseover/onmouseout事件发生时的div背景色，但是代码执行后，网页上没有任何变化，请帮忙看看是什么问题。foreach (HtmlElement div in webBrowser1.Document.Window.Frames[1].Document.GetElementsByTagName("DIV"))
                {
                    if (div.GetAttribute("rowIndex")=="0" && div.InnerHtml.IndexOf(">回复</BUTTON>") >= 0)
                    {
                        div.Style = "background-color=#D3FF93";
//下面两句代码的效果没有生效
                        div.SetAttribute("onmouseover", "\"this.style.backgroundColor='#8CEA00'\"");
                        div.SetAttribute("onmouseout", "\"this.style.backgroundColor='#D3FF93'\"");
                    }
                }===============================
下面是HTML的代码
<HTML>
<TBODY>
<DIV style="WIDTH: 300px" class="123" rowIndex="0">
<TABLE>
<TBODY>
<TR>
<TD><DIV><A>123</A></DIV></TD>
<TD><DIV>1234</DIV></TD>
<TD><DIV>aaa</DIV></TD>
<TD>
<TABLE>
<TBODY>
<TR>
<TD><I></I></TD>
<TD><EM><BUTTON>回复</BUTTON></EM></TD>
</TR></TBODY></TABLE></TD></TR></TBODY></TABLE></DIV>
<DIV style="WIDTH: 300px;background-Color:#d3a4ff" class="123" rowIndex="1" onmouseover="this.style.backgroundColor='#921AFF'" onmouseout="this.style.backgroundColor='#d3a4ff'">
<TABLE>
<TBODY>
<TR>
<TD><DIV><A>123</A></DIV></TD>
<TD><DIV>1234</DIV></TD>
<TD><DIV>aaa</DIV></TD>
<TD>
<TABLE>
<TBODY>
<TR>
<TD><I></I></TD>
<TD><EM><BUTTON>查看</BUTTON></EM></TD>
</TR></TBODY></TABLE></TD></TR></TBODY></TABLE></DIV>
<DIV style="WIDTH: 300px;background-Color:#d3a4ff" class="123" rowIndex="2" onmouseover="this.style.backgroundColor='#921AFF'" onmouseout="this.style.backgroundColor='#d3a4ff'">
<TABLE>
<TBODY>
<TR>
<TD><DIV><A>123</A></DIV></TD>
<TD><DIV>1234</DIV></TD>
<TD><DIV>aaa</DIV></TD>
<TD>
<TABLE>
<TBODY>
<TR>
<TD><I></I></TD>
<TD><EM><BUTTON>查看</BUTTON></EM></TD>
</TR></TBODY></TABLE></TD></TR></TBODY></TABLE></DIV>
</TBODY>
</HTML>webbrowserdivonmouseoveronmouseoutbackgroundColor