Javascript 如何得到input type="radio" 的值？

<script language="JavaScript">

<!--



function chk()

{

var obj = document.getElementsByName('imgposition');



for (i=0;i<obj.length;i++)

{



if (obj[i].checked)

{

alert(obj[i].value);

return;

}

}

alert('你没选');

}

//-->

</script>

<form name=form1>

<input type="radio" name="imgposition" value="1">

<input type="radio" name="imgposition" value="2">

<input type="radio" name="imgposition" value="3">

</form>

<input type="button" onclick="chk()">



for example:





<INPUT type=radio name="radio" CHECKED>1-10 years old

<INPUT type=radio name="radio">11 years old

<INPUT type=radio name="radio">12-120 years old

This example uses script to detect which radio button the user selects.



<SCRIPT>

function detect()





{

if (radio[0].checked)

alert("You're between 1 and 10 years old.")

else if (radio[1].checked)

alert("You're 11 years old.")

else

alert("You're between 12 and 120 years old.")

}

</SCRIPT>



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