//jquery

$("#input_title").keydown(function(e){
e = e||window.event;// Firefox window.event
if((e.keyCode || e.which) == 13){
return false;
}

});

//js

document.onkeypress=function(e) {
e = e||window.event;//Firefox window.event
if((e.keyCode || e.which) == 13){
return false;
}
}