值替换

Question

<form name="myForm" method="GET" ">
  <input type="text" name="txtName" >  
     <a id="mylink" href="">Submit</a></p>
      <script>
         document.getElementById("mylink").href = "login.do?txtName=" + document.getElementsByName("txtName")[0].value;
      </script>
    </form>

Answer 1

<script>
document.forms["myForm"].txtName.value = 123;
</script>

Answer 2

<form name="myForm" method="GET" ">
  <input type="text" name="txtName" >  
     <a href="login.do?txtName=123" onClick="document.getElementById('txtName').value = 123">Submit</a></p>
    </form>