输入框的文字限制字数,用微软拼音输入内容会被清空或者部分清空

对输入框的文字限制字数,用微软拼音输入输入的时候,只要一达到输入限制,就跳出"字数不能超过57" ,这时,问题出现了,前面输入的内容会被清空或者部分清空

<script language="javascript">
function gbcount(message,total,used,remain)
{
  var max;
  max = total.value;
  if(message.value.length > max){
    message.value = message.value.substring(0,max);
    used.value = max;
    remain.value = 0;
    alert('字数不能超过57!');
  }
  else{
    used.value = message.value.length;
    remain.value = max - used.value;
  }
}

</script>
<form name="form1" method="post"   action="do.asp">
<textarea name="sms_content" cols="48" rows="8"   id="sms_content" onkeydown=gbcount(this.form.sms_content,this.form.total,this.form.used,this.form.remain); onkeyup=gbcount(this.form.sms_content,this.form.total,this.form.used,this.form.remain); ></textarea>
最多字数：<input name=total disabled class="FormStyle" value=57 size=3 maxlength=4>
                      已用字数：
                      <input name=used disabled class="FormStyle" value=0 size=3 maxlength=4>
                      剩余字数：
                      <input name=remain disabled class="FormStyle" size=3 maxlength=4>
</form>

 

解决方法

<script language="javascript">
function gbcount(message,total,used,remain)
{
  var max;
  max = total.value;
  if(message.value.length > max){
    used.value = max;
    remain.value = 0;
    alert('字数不能超过57!');
 message.value = message.value.substring(0,max);
  }
  else{
    used.value = message.value.length;
    remain.value = max - used.value;
  }
}
</script>
<form name="form1" method="post"   action="do.asp">
<textarea name="sms_content" cols="48" rows="8"   id="sms_content" onkeydown=gbcount(this.form.sms_content,this.form.total,this.form.used,this.form.remain); onkeyup=gbcount(this.form.sms_content,this.form.total,this.form.used,this.form.remain); ></textarea>
最多字数：<input name=total disabled class="FormStyle" value=57 size=3 maxlength=4>
                      已用字数：
                      <input name=used disabled class="FormStyle" value=0 size=3 maxlength=4>
                      剩余字数：
                      <input name=remain disabled class="FormStyle" size=3 maxlength=4>
</form>

 

 

不需要alert的话可以采用这样的方法

   document.getElementById("sms_content").blur();
 message.value = message.value.substring(0,max);
   document.getElementById("sms_content").focus();