通过改变A的大小来改变当前页面字体的大小,这一块要怎么写
回复讨论(解决方案)
单纯的css不能完成这个任务需求，需要js的干预。
window.onload = function(){ var content = document.getElementById('content'); var btn = document.getElementById('btn'); var btns = btn.getElementsByTagName('button'); for(var i = 0; i < btns.length; i++){ btns[i].index = i; btns[i].onclick = function(){ changeSize(this.index); } } var arr = ['12px', '14px', '16px']; function changeSize(n){ content.style.fontSize = arr[n]; }}; 完整的代码：
<!doctype html><html><head> <meta charset="UTF-8"> <title></title></head><body><div id="btn"> <button>小</button> <button>中</button> <button>大</button></div><div id="content"> <p>1. 健康</p> <ul> <li>你会精力充沛，呼吸顺畅</li> <li>你会患上肺癌、呼吸系统疾病、心脏病</li> </ul></div><script> window.onload = function(){ var content = document.getElementById('content'); var btn = document.getElementById('btn'); var btns = btn.getElementsByTagName('button'); for(var i = 0; i < btns.length; i++){ btns[i].index = i; btns[i].onclick = function(){ changeSize(this.index); } } var arr = ['12px', '14px', '16px']; function changeSize(n){ content.style.fontSize = arr[n]; } };</script></body></html>
“Ems”: em，大小不固定 ,成为相对单位（body则相对浏览器的默认字体设置，子集相对父级）， 浏览器默认设置字体大小为16px , 则1em = 16px , 且其可扩展，2em = 32px , 目前常用的字体大小px换算成em , 他们把字体大小用em 来表示，通过改变bodyd的什么就可以改变字体的大小请问这种写法要怎么写？？
“Ems”: em，大小不固定 ,成为相对单位（body则相对浏览器的默认字体设置，子集相对父级）， 浏览器默认设置字体大小为16px , 则1em = 16px , 且其可扩展，2em = 32px , 目前常用的字体大小px换算成em , 他们把字体大小用em 来表示，通过改变bodyd的什么就可以改变字体的大小请问这种写法要怎么写？？
不建议直接改body,改body容易问题，所有字体都会变成同一个大小。等明天写个实例给你。
“Ems”: em，大小不固定 ,成为相对单位（body则相对浏览器的默认字体设置，子集相对父级）， 浏览器默认设置字体大小为16px , 则1em = 16px , 且其可扩展，2em = 32px , 目前常用的字体大小px换算成em , 他们把字体大小用em 来表示，通过改变bodyd的什么就可以改变字体的大小请问这种写法要怎么写？？
不建议直接改body,改body容易问题，所有字体都会变成同一个大小。等明天写个实例给你。
谢谢!
我需要的效果是通过点击A的大小,来改变所有页面字体的大小
如果字体大小是可以改变的,我就用em表示,如果是固定大小的就有px写死
$("html").css("font-size","12px");
<HTML><HEAD><TITLE>特定区域文字控制</TITLE><STYLE type=text/css>BODY { MARGIN-TOP: 0px; FONT-SIZE: 9pt; MARGIN-LEFT: 0px; MARGIN-RIGHT: 0px; FONT-FAMILY: "宋体"}A { FONT-WEIGHT: 400; FONT-SIZE: 9pt; COLOR: black; TEXT-DECORATION: none}A:hover { FONT-WEIGHT: 400; FONT-SIZE: 9pt; COLOR: red; TEXT-DECORATION: underline}A:active { FONT: 9pt "宋体"; CURSOR: hand; COLOR: #ff0033}.STYLE1 { font-size: 40px; font-family: "华文行楷"; color: #990000;}.STYLE2 { font-size: 30px; font-weight: bold; font-family: "黑体"; color: #0000FF;}</STYLE><META http-equiv=Content-Type content="text/html; charset=gb2312"><META content="MSHTML 6.00.2900.2180" name=GENERATOR></HEAD><BODY bgColor=#fef4d9><BR><BR><CENTER><TABLE borderColor=#993399 border=5 borderlight="green"> <TBODY> <TR> <TD align=middle> <SCRIPT language=JavaScript>function doZoom(size){ document.getElementById('zoom').style.fontSize=size+'px'}</SCRIPT> <TABLE style="BORDER-RIGHT: #336699 1px solid; BORDER-TOP: #336699 1px solid; BORDER-LEFT: #336699 1px solid; BORDER-BOTTOM: #336699 1px solid" cellSpacing=0 width=200 align=center bgColor=#93bee2 border=0> <TBODY> <TR> <TD style="BORDER-BOTTOM: #336699 1px solid" width="83%" bgColor=#00FFFF>[<A href="javascript:doZoom(20)">大字</A> <A href="javascript:doZoom(14)">中字</A> <A href="javascript:doZoom(9)">小字</A>] <DIV></DIV></TD></TR> <TR bgColor=#ffffff> <TD id=zoom colSpan=2><div align="center">文字大小变化哦</div></TD></TR></TBODY></TABLE></TD></TR></TBODY></TABLE></CENTER></BODY></HTML> 
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