在Button3_Click事件里怎么把input中checkbox类型的都找出来？

Question

 <form id="form1" runat="server">
    <div>
    <input  type="button" id="button1" runat="server" value="ok"/>
    <input  type="checkbox" id="checkbox1" runat="server" title="cb1"/>
    <input  type="checkbox" id="checkbox2" runat="server" title="cb2"/>
    <input  type="checkbox" id="checkbox3" runat="server" title="cb3"/>
    <input  type="button" id="button2" runat="server" value="cancel"/>
        <asp:Button ID="Button3" runat="server" OnClick="Button3_Click" Text="Button" /></div>
    </form>

Answer 1

foreach (Control c in this.form1.Controls)
            {
                if (c is HtmlInputCheckBox)
                {
                    HtmlInputCheckBox b= c as HtmlInputCheckBox;
                   
                }
            }

Answer 2

foreach(Control   ctl   in   Page.FindControl("Form1").Controls)  
  {  
            if(ctl   is   HtmlInputCheckBox )  
            {  
               if((ctl   as   HtmlInputCheckBox ).Checked)   
                 {                 }  
           }  
  }

Answer 3

foreach (Control c in this.form1.Controls) 
            { 
                if (c is HtmlInputCheckBox) 
                { 
                    HtmlInputCheckBox b= c as HtmlInputCheckBox; 
                  
                } 
            }

Answer 4

//测试通过！速度慢了！
foreach (Control control in this.form1.Controls)
        {
            if (control is HtmlInputCheckBox)
            {
                HtmlInputCheckBox cbx = (HtmlInputCheckBox)control;
                cbx.Checked = true;
            }
        }

Answer 5

function findcontrol()
{
  var inputs = document.body.getElementByTagName("input");
  var t=0;
  for(var i=0;i<inputs.length;i++ )
  {
    if(inputs[i].type == "checkbox")
     t++;
  }
  alert("选择了"+t+"个checkbox")
}

Answer 6

<form id="form1" runat="server">
    <div>
    <input  type="button" id="button1" value="ok"/>
    <input  type="checkbox" id="cb "title="cb1"/>
    <input  type="checkbox" id="cb"  title="cb2"/>
    <input  type="checkbox" id="cb"title="cb3"/>
    <input  type="button" id="button2" runat="server" value="cancel"/>
        <asp:Button ID="Button3" runat="server" OnClick="Button3_Click" Text="Button" /> </div>
    </form>
这样怎么找出id是cb的input