userAgentLowerCase = navigator.userAgent.toLowerCase();
 
function resizeTextarea(t) {
  if ( !t.initialRows ) t.initialRows = t.rows;
 
  a = t.value.split('\n');
  b=0;
  for (x=0; x < a.length; x++) {
    if (a[x].length >= t.cols) b+= Math.floor(a[x].length / t.cols);
  }
 
  b += a.length;
 
  if (userAgentLowerCase.indexOf('opera') != -1) b += 2;
 
  if (b > t.rows || b < t.rows)
    t.rows = (b < t.initialRows ? t.initialRows : b);
}

function checkLetter(e){
	var unicode=e.charCode? e.charCode : e.keyCode
	if (unicode!=8){ //if the key isn't the backspace key (which we should allow)
		if (unicode==94 || unicode==124)
			return false //disable key press
	}
}

function adjustHeight(textarea){
    var dif = textarea.scrollHeight - textarea.clientHeight;
    if (dif){
        if (isNaN(parseInt(textarea.style.height))){
            textarea.style.height = textarea.scrollHeight + "px";
        }else{
            if (dif>0) {
				if (userAgentLowerCase.indexOf('opera') != -1) {
					 textarea.style.height = 100 + "px";}
				else {
					textarea.style.height = parseInt(textarea.style.height) + dif + "px";}
			}
			else {
				textarea.style.height = 100 + "px";
			}
        }
    }	
}

function limitText(limitField, limitNum) {
	if (limitField.value.length > limitNum) {
		limitField.value = limitField.value.substring(0, limitNum);
	}
}