jquery 控制文本输入的字数

<textarea maxlength="200" id="remarks" onkeyup="title_len();"></textarea>
<span id="titlelen" style="float:right;">0/100</span>

<script>

function title_len(){
var length = 100;
var value = $('#remarks').val().length;
var in_len = length-value;
if(in_len >= 0){
$(":button").css("background","#83A4D4");
$(".faceConsultation_btn").attr("disabled",false);
var string = "<span>"+value+"/100</span>";
}else{
$(":button").css("background","#E0E0E0");
$(".faceConsultation_btn").attr("disabled",true);
var string = "<span style="color:#FF0000">"+value+"</span>/100";
}
$('#titlelen').html(string);
}

</script>

在手机上使控制字数  onkeyup 事件在（ios系统）手机上效果不好   用  oninput 事件