webbrowser在html中写入内容并添加js

在html中写入内容，并添加js

private void btnTestJs_Click(object sender, EventArgs e)
{
this.webBrowser1.Navigate("about:blank");
this.webBrowser1.Document.Write("testBody");//make the this.webBrowser1.Document.Body is not null

HtmlElement he = this.webBrowser1.Document.CreateElement("script");
he.SetAttribute("type","text/javascript");
he.SetAttribute("text","alert('test');");
this.webBrowser1.Document.Body.AppendChild(he);//add element

}

.csharpcode, .csharpcode pre
{
font-size: small;
color: black;
font-family: consolas, "Courier New", courier, monospace;
background-color: #ffffff;
/*white-space: pre;*/
}
.csharpcode pre { margin: 0em; }
.csharpcode .rem { color: #008000; }
.csharpcode .kwrd { color: #0000ff; }
.csharpcode .str { color: #006080; }
.csharpcode .op { color: #0000c0; }
.csharpcode .preproc { color: #cc6633; }
.csharpcode .asp { background-color: #ffff00; }
.csharpcode .html { color: #800000; }
.csharpcode .attr { color: #ff0000; }
.csharpcode .alt
{
background-color: #f4f4f4;
width: 100%;
margin: 0em;
}
.csharpcode .lnum { color: #606060; }