)入力ボックスのパスワードを10文字設定します.

<span class="span"><span id="stay" style="display: none">       :<span id="txtCount">span>   <br>span>span>
<input type="password"   id="password" name="password">
<script language="JavaScript">
    var lim=new limit();
    lim.txtNote=document.getElementById("password");
    lim.txtLimit=document.getElementById("txtCount");
    lim.limitCount=10;
    lim.init();
    function limit(){
        var txtNote;    //   
        var txtLimit;   //     input
        var limitCount; //     
        var txtlength;  //     ，      
        this.init=function(){
            txtNote=this.txtNote;
            txtLimit=this.txtLimit;
            limitCount=this.limitCount;
            txtNote.oninput=function(){wordsLimit()};txtNote.oninput=function(){wordsLimit()};
            txtLimit.innerText=limitCount;
        };
        function wordsLimit(){
            var noteCount=txtNote.value.length;
            var InPut=document.getElementById("password").value.length;
            if(InPut<10){
                document.getElementById("stay").style.display="none";
                return
            }
            if(InPut>=10){
                document.getElementById("stay").style.display="inline";
                document.getElementById("stay").style.color="green";
            }
            if(noteCount>limitCount){
                txtNote.value=txtNote.value.substring(0,limitCount);
                txtLimit.innerText=0;
            }else{
                txtLimit.innerText=limitCount-noteCount;
            }
            txtlength=txtNote.value.length;//          
        }
    }
script>