<script>
function selectC()
{
 var oSel=document.getElementsByName("name")[0];
 var oInp=document.getElementsByName("fax")[0];
 var Value=oSel.options[oSel.selectedIndex].value;
 if(parseInt(Value)>0)
  oInp.value="LII"+Value+"&FileName&";
 else
  oInp.value="";
}

</script>
<select name="name" onchange="selectC()">
 <option selected>-請選擇-</option>
   <option value="1">美國</option>
 <option value="2">中國</option>
  </select>

<input type="text" name="fax" size="20">

////////////////////////////////////////////////////////////////
<textarea id="textarea1"></textarea><input type="button" value="機選一注" onclick="show()">
<script language=javascript>
        function show()
        {
            var obj=document.getElementById("textarea1")
            var temp=new Array(1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22)
            var strResult=new Array()
            for(var j=0;j<5;j++)
            {
                var i=Math.floor(Math.random()*(22-j))
                strResult[strResult.length]=temp[i]
                temp.splice(i,1)
            }
            obj.value=strResult.join(",")
        }
</script>

/////////////////////////////////////////////////////////////////
<textarea id="textarea1" style="height:200;widht:200"></textarea><input type="button" value="機選五注" onclick="show()">
<script language=javascript>
        function getNum()
        {
           
            var temp=new Array('01','02','03','04','05','06','07','08','09','10','11','12','13','14','15','16','17','18','19','20','21','22')
            var strResult=new Array()
            for(var j=0;j<5;j++)
            {
                var i=Math.floor(Math.random()*(22-j))
                strResult[strResult.length]=temp[i]
                temp.splice(i,1)
            }
            return strResult.join(",")
           
        }
        function show(){
            var obj=document.getElementById("textarea1")
            var result=new Array()
            for(var i=0;i<5;i++)
            {
                result[i]=getNum()
            }
            obj.value=result.join("\n")
        }
</script>


////////////////////////////////////////////////////////////////////
<textarea id="textarea1" style="height:200;widht:200"></textarea><input type="button" value="機選五注" onclick="show()">
<script language=javascript>
        function getNum()
        {
           
            var temp=new Array('01','02','03','04','05','06','07','08','09','10','11','12','13','14','15','16','17','18','19','20','21','22')
            var strResult=new Array()
            for(var j=0;j<5;j++)
            {
                var i=Math.floor(Math.random()*(22-j))
                strResult[strResult.length]=temp[i]
                temp.splice(i,1)
            }
            return strResult.join(",")
           
        }
        function show(){
           document.getElementById("textarea1").value=""
                        showEach();
           
        }
        i=0;
        function showEach()
        {
           
            var obj=document.getElementById("textarea1")
            obj.value=obj.value+"\n"+getNum()
            if(i++>3)i=0
            else
            setTimeout("showEach()",500)
           
        }
</script>

////////////////////////////////////////////////////////////////

1.通過getElementById() 方法獲得，必須為文本框設定ID值，該方法獲得的是一個對象的應用(返回值

為:Object)，要獲得文本框的值需添加屬性值--value,如:
<input type="text" size="10" id="port11" name="port11" />

獲值代碼：document.getElementById("port11").value;

另：要獲得標簽<h1>中間的值，方法如下：
<h1 id="you">12345</h1>
document.getElementById("you").innerHTML;
返回值為：12345

----------------------------------------------------------------------------------------

2.如果是表單(<form>)中的文本框，還可以通過以下方式獲得值:

<form name="form1" method="post" action="manager.do?action=login">
<tr><td >會員編號：</td>
<td ><input name="memberNo" type="text" id="memberNo" size="21" ></td>

<td ><input name="Submit" type="submit" value="確定" onClick="return check(form1)"></tr>
</form>

js中的代碼：function check(form){var str = form.memberNo.value;}

注意點：表單需指定名稱(name)，方法中需指定傳入的參數對象。