webBrowser控件打开www.baidu.com,自动搜索里面是否有 网页 这两个字

//载入窗体的时候打开网页
        private void Form1_Load(object sender, EventArgs e)
        {
            webBrowser1.Navigate("www.baidu.com");
        }


//判断是否含有textbox1中输入的关键字
        private void button1_Click(object sender, EventArgs e)
        {
            if (textBox1.Text.Length == 0)
            {
                MessageBox.Show("输入需要查找的内容!");
                return;
            }

            String s = webBrowser1.Document.Body.InnerHtml;
            Boolean i = s.Contains(textBox1.Text);
            if (i)
                MessageBox.Show("网页中有关键字：" + textBox1.Text, "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
            else
                MessageBox.Show("无法查找关键字：" + textBox1.Text, "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
        }