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<div id="mometer">
    <div id="hot"></div>
    <span>
        <div id="Hgheader">0℃</div>
        <div id="Hg"></div>
    </span>
</div>
  <input name="aa" type="text" value="请输入0-100的数值" id="num"/>
  <input name="" type="button" id="Risk" value="查看度数" />

#num{color:#999;}
#mometer{position:relative;    height:100px;width:15px;background-color:#CCC;margin:50px;}
span{position:absolute;display:block;bottom:0px;width:40px;}
#Hgheader{height:15px;line-height:15px;color:#FF0000;font-size:14px;font-family:Arial, Helvetica, sans-serif;
border-bottom:#f00 1px solid;left:-40px;position:relative;}
#Hg{height:0px;    font-size:0px;background-color:#C00;width:15px;}
#hot{height:100px;width:15px; background-color:#FF0; position:absolute; top:0; left:0;}

$(document).ready(function(){
$("#hot").fadeTo(0,0);//初始透明度为0；
$('#num').click(function(){this.select();})
$('#Risk').click(function(){
    inputvalue=$('#num').val();//val()获取input元素的值，另外还可以用attr("value")来获取；
    var inputnum=parseInt(inputvalue);
    if($('#num').val().search("^-?\\d+$") != 0){
        alert("请输入一个0-100的整数!");
        return false;
        }else{
        $("#Hgheader").html(inputvalue+"℃");
        if(inputnum>=100){
        inputnum=100;
        $('#num').val(100)
        $("#Hgheader").html(100+"℃");
    }else if(inputnum<=0){
        inputnum=0;
        $('#num').val(0)
        $("#Hgheader").html(0+"℃");
    }
        }
    var Columnhe=inputnum/100;
    $("#Hg").animate({height:inputnum},'show');
    $("#hot").fadeTo('slow',Columnhe);
//在这里把html换成text效果也是一样的;
});
});