Question : javascript

Hello i have 5 textbox with the same name , the only thing that change is the number at the end of the name
let say:

document.Invoice.txtName1.value
document.Invoice.txtName2.value
document.Invoice.txtName3.value

how can i just change the number for a variable:

something like

var x = 1;

document.Invoice.txtName(x).value
document.Invoice.txtName(x).value
document.Invoice.txtName(x).value

so i can run a for 3 times and don,t have to write all the code for each field.

Answer : javascript

use the id attribute for this

<input type="text" id='txt1'>
<input type="text" id='txt2'>
<input type="text" id='txt3'>

for ( var counter = 1; counter <= 3; counter++ )
{
alert(document.getElementById("txt" + counter ).value);
}