How to check if the textbox is empty?

in the case of checking if a textbox is empty, i know how to do it.
but in the case of having a table where you get/retrieve all the rows in the database, i dont know how to it.
Below is the sample code of what i meant. I have this table where i retrieve all the rows in the DB. each row, there is a textbox where the value is 1+1+1+1….., how will i check all these textboxes if they are empty?

<script language=”JavaScript” type=”text/JavaScript”>
function checkField()
{
var field = document.frmCheck.[COLOR=red]TEXTBOXES IN VECTOR[/COLOR].value;
if (field == ”)
{
alert(‘Please input field!’);
return false;
}
}
</script>

<form name=”frmCheck” method=”post” action=””>
<table width=”75%” border=”1″>
<%

int x = 0;

int count = 1;
while(x < vVector.size())
{
%>

<tr>
<td>&nbsp;</td>
<td>&nbsp;<input name=”<%=count%>” type=”text” id=”<%=count%>”></td>
<%
x = x + 3;
count = count + 1;
}
%>
</tr>
</table>
</form>

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