Text Area Max length validation

function count1(value,evt,ref) {
var charCode = (evt.which != undefined) ? evt.which : evt.keyCode;
if(ref == 'address') {
if(value.length>100){
if(charCode==8) {
return true;
}
return false;
}
}
}


onkeypress="return count1(value,event,'address')"