JS实现textarea对象Maxlength属性

转自[http://www.itercn.com/wp/archives/155.html]

<form id=”8848so” name=”8848so” action=”http://www.8848so.com” method=”post”>
<textarea id=”content”></textarea>
<span id=”tip”></span>
</form>
<!–
= * = = * = = * = = * = = * = = * = = * = = * = = * = = * = = * = = *
*    作 者：  我本有心
–>
<script language=“javascript“ type=“text/javascript“>
fixedLength(“content“,“tip“,5); //调用说明：textarea对象ID,span或div对象ID(用于显示提示信息),最大允许字符数

function fixedLength(textareaID,tipsID,wordLength)
{
    var textarea = document.getElementById(textareaID);
    var span = document.getElementById(tipsID);
   
    textarea.onkeyup = function() {onkeyupLength(textarea,span,wordLength);}; //输入事件
    textarea.onblur = textarea.onkeyup;
    textarea.onpaste = function () //粘贴之前事件
    {
        if (textarea.value.length >= wordLength)
        {
            var noneStr = “”;
            window.clipboardData.setData(“text“,noneStr);
        }
        else
        {
            window.clipboardData.setData(“text“,window.clipboardData.getData(“text“).substr(0,wordLength - textarea.value.length));
            var diffLength = textarea.value.length + window.clipboardData.getData(“text“).length;
            lengthTips(span,wordLength,diffLength);
        }
    };
   
    textarea.ondrop = function () //拖拽事件
    {
        if (textarea.value.length >= wordLength)
        {
            var noneStr = “”;
            window.event.dataTransfer.setData(“text“,noneStr);
        }
        else
        {
            window.event.dataTransfer.setData(“text“,window.event.dataTransfer.getData(“text“).substr(0,wordLength - textarea.value.length));
            var diffLength = textarea.value.length + window.event.dataTransfer.getData(“text“).length;
            lengthTips(span,wordLength,diffLength);
        }   
    }
}function lengthTips(span,wordLength,textareaLength)
{span.innerHTML = “共:“ + wordLength + “己输:“ + textareaLength  + “剩:“ + (wordLength - textareaLength);}
</script>

 

function onkeyupLength(textarea,span,wordLength)
{
    var textareaLength = textarea.value.length;
   
    if (wordLength - textareaLength >= 0)
    {lengthTips(span,wordLength,textareaLength);}
    else
    {textarea.value = textarea.value.substr(0
,wordLength);}
}

来源：https://www.cnblogs.com/cuoluan/archive/2009/09/10/1564220.html