Acessing Dynamically Generated Form Elements..

I have form elements which dynamically generated like this...

<form name="formA" ...>
<input type="select" name="text_1" ...>
<input type="select" name="text_2" ...>
<input type="select" name="text_3" ...>
<input type="select" name="text_4" ...>
</form>

And I doing some validation like this.
function checkvalue()
{
var f = document.forms['formA'];
var eLen = f.elements.length;
for (var i=0; i<eLen; i++) {
if(f.elements[i].name == "text_" + i)
{ alert ( f.elements[i].name); }
else { alert (f.elements[i].name); }
}

It never goes into first part of if statement.. Is there a way I can
access these kind form elements..