限制文本框，文本域输入的字符数量

function limitCharsNum(charsNumSpanId,id,max)
{ 
    setTimeout(function(){
       var valLen=$("#"+id).val().length;
       console.log(max);
       if(valLen>max)
       {
          console.log(valLen);
          $("#"+id).val($("#"+id).val().substring(0,max));
       }

       $("#"+charsNumSpanId).text((max-valLen)<=0?0:(max-valLen));
    }, 100);  
}

function initLimitCharsNum(charsNumSpanId,id,max)
{ 
     $("#"+id).attr("onpaste","limitCharsNum('"+charsNumSpanId+"','"+id+"',"+max+")");
     $("#"+id).attr("oncut","limitCharsNum('"+charsNumSpanId+"','"+id+"',"+max+")");
     $("#"+id).attr("onkeydown","limitCharsNum('"+charsNumSpanId+"','"+id+"',"+max+")");
     $("#"+id).attr("onkeyup","limitCharsNum('"+charsNumSpanId+"','"+id+"',"+max+")");
     $("#"+id).attr("ondrop","limitCharsNum('"+charsNumSpanId+"','"+id+"',"+max+")");
}

例子：

    initLimitCharsNum('remainderNum1','ztinput1',100);
    initLimitCharsNum('remainderNum2','fsnrtextarea1',100);