// JavaScript Document
function textCounter(txtfield, cntVal, maxlimit) {

if (document.getElementById(txtfield).value.length > maxlimit) // if too long...trim it!
document.getElementById(txtfield).value = document.getElementById(txtfield).value.substring(0, maxlimit);
// otherwise, update 'characters left' counter
else 
document.getElementById(cntVal).innerHTML = maxlimit - document.getElementById(txtfield).value.length;
}