style.css
* { margin:0; padding:0; } .msg {width:300px; margin:100px; } .msg_caption { width:100%; overflow:hidden; margin-bottom:1px;} .msg_caption span { display:block; float:left; margin:0 2px; padding:4px 10px; background:#898989; cursor:pointer;font-size:12px;color:white; } .msg textarea{ width:300px; height:80px;height:100px;border:1px solid #000;}
demo.html
<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title></title> <link rel="stylesheet" type="text/css" href="css/style.css" /> <script src="js/jquery-1.10.1.min.js" type="text/javascript"></script> <script type="text/javascript"> $(function(){ $("span").click(function(){ var thisEle = $("#para").css("font-size"); var textFontSize = parseFloat(thisEle , 10); var unit = thisEle.slice(-2); //获取单位 var cName = $(this).attr("class"); if(cName == "bigger"){ if( textFontSize <= 22 ){ textFontSize += 2; } }else if(cName == "smaller"){ if( textFontSize >= 12 ){ textFontSize -= 2; } } $("#para").css("font-size", textFontSize + unit); }); }); </script> </head> <body> <div class="msg"> <div class="msg_caption"> <span class="bigger" >放大</span> <span class="smaller" >缩小</span> </div> <div> <p id="para"> 阅谁问君诵,水落清香浮。阅谁问君诵,水落清香浮。阅谁问君诵,水落清香浮。 阅谁问君诵,水落清香浮。阅谁问君诵,水落清香浮。阅谁问君诵,水落清香浮。 阅谁问君诵,水落清香浮。阅谁问君诵,水落清香浮。阅谁问君诵,水落清香浮。 </p> </div> </div> </body> </html>
效果图: