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




function filterInput(event) {

    //ie keycodes
	if (event.which == null){

					
	    if (event.keyCode  >= 65  && event.keyCode <= 90) return true;		
		
	    if (event.keyCode  >= 97  && event.keyCode <= 122) return true;		
	    
	    if (event.keyCode  = 95) return true;		
		
	    
	    if (event.keyCode  >= 48  && event.keyCode <= 57) return true;		
	    
	   

	    
	    
	}
	

	//firefox
    
	//A-Z
	if (event &&  event.which >= 65  && event.which <= 90) return true;
	//a-z
	if (event &&  event.which >= 97  && event.which <= 122) return true;
	//underscore
	if (event &&  event.which == 95) return true; 
	// numbers
	if (event &&  event.which >= 48  && event.which <= 57) return true;
	
	

	
	//enter
    if (event &&  event.which == 13) return true;        
	//backspace
    if (event &&  event.which == 8) return true;        
	//delete
    if (event &&  event.which == 127) return true;
    
    
	//tab
	if (event.keyCode == 9) return true;
	//shift
	if (event.keyCode == 16) return true;
	//caps lock
	if (event.keyCode == 20) return true;
	//end
	if (event.keyCode == 35) return true;
	//home
	if (event.keyCode == 36) return true;
	//left arrow
	if (event.keyCode == 37) return true;
	//right arrow
	if (event.keyCode == 39) return true;
	//up arrow
	if (event.keyCode == 38) return true;
	//down arrow
	if (event.keyCode == 40) return true;
	//insert
	if (event.keyCode == 45) return true;
	//delete
	if (event.keyCode == 46) return true;
    
    
    return false;
    
}