Add/Delete ผมได้ลองเอา code ตามด้านล่างนี้ไปใช้ครับ ดีมาก ๆ เลยครับ แต่ผมอยากจะขอถามหน่อยครับ

<script language="javascript">
function fncCreateElement(){

var mySpan = document.getElementById('mySpan');

var myLine = document.getElementById('hdnLine');
myLine.value++;

var myElement1 = document.createElement('input');
myElement1.setAttribute('type',"text");
myElement1.setAttribute('name',"text1[]");
myElement1.setAttribute('id',"fil"+myLine.value);
mySpan.appendChild(myElement1); 

// Create <br>
var myElement2 = document.createElement('<br>');
myElement2.setAttribute('id',"br"+myLine.value);
mySpan.appendChild(myElement2);
}

function fncDeleteElement(){

var mySpan = document.getElementById('mySpan');

var myLine = document.getElementById('hdnLine');

if(myLine.value > 1 )
{

// Remove input file
var deleteEle = document.getElementById("fil"+myLine.value);
mySpan.removeChild(deleteEle);

// Remove <br>
var deleteBr = document.getElementById("br"+myLine.value);
mySpan.removeChild(deleteBr);

myLine.value--;
}
}
</script>

<form action="php_multiple_upload2.php" method="post" name="form1" enctype="multipart/form-data">
<input type="text" name="text1[]"> 
<input name="btnCreate" type="button" value="+" onClick="JavaScript:fncCreateElement();">
<input name="btnDelete" type="button" value="-" onClick="JavaScript:fncDeleteElement();"><br> 
<span id="mySpan"></span> 
<input id="hdnLine" name="hdnLine" type="hidden" value="1">
<input name="btnSubmit" type="submit" value="Submit">
</form>