转:https://blog.csdn.net/m0_37893932/article/details/70157817
//移动端微信公众号开发
<div class="weui-cell__bd">
<textarea id="content" class="weui-textarea" placeholder="新消息内容"
rows="3">
</textarea>
<div class="weui-textarea-counter">
<span class="contentcount">0</span>/200
</div>
</div>
//web端业务开发
<div class="modal-body" style="box-sizing: border-box;">
<form id="newtaskform" class="form-horizontal"></form>
</div>
$('#content').bind('input propertychange', function () {
var fizeNum = $(this).val().length;
if (fizeNum > 200) {
var char = $(this).val();
char = char.substr(0, 200);
$(this).val(char);
fizeNum = 200;
tooltipsShow('消息内容不能超过200字');
}
$(this).parent().find('.contentcount').text(fizeNum);
});