首先我们看看document.compatMode(兼容模式):
document.compatMode它有两种可能的返回值:BackCompat和CSS1Compat,
document.compatMode的使用,感觉这个对于我们开发兼容性的web页面还是很有帮助,我们都知道,IE对盒模型的渲染在 Standards Mode和Quirks Mode是有很大差别的,在Standards Mode下对于盒模型的解释和其他的标准浏览器是一样,但在Quirks Mode模式下则有很大差别,而在不声明Doctype的情况下,IE默认又是Quirks Mode。所以为兼容性考虑,我们可能需要获取当前的文档渲染方式。
BackCompat Standards-compliant mode is not switched on. (Quirks Mode)
CSS1Compat Standards-compliant mode is switched on. (Standards Mode)
在实际的项目中,我们还需要在获取浏览是否IE,这样就可以得到IE的渲染模式了。在Ext中的代码:isBorderBox=isIE&&!isStrict。
当文档有了标准声明时, document.compatMode 的值就等于 "CSS1compat", 因此, 我们可以根据 document.compatMode 的值来判断文档是否加了标准声明
var height = document.compatMode=="CSS1Compat" ? document.documentElement.clientHeight : document.body.clientHeight;
document.compatMode用来判断当前浏览器采用的渲染方式。
官方解释:
BackCompat:标准兼容模式关闭。
CSS1Compat:标准兼容模式开启。
当document.compatMode等于BackCompat时,浏览器客户区宽度是document.body.clientWidth;
当document.compatMode等于CSS1Compat时,浏览器客户区宽度是document.documentElement.clientWidth。
浏览器客户区高度、滚动条高度、滚动条的Left、滚动条的Top等等都是上面的情况。
一个准确获取网页客户区的宽高、滚动条宽高、滚动条Left和Top的代码:
if (document.compatMode == "BackCompat") { cWidth = document.body.clientWidth; cHeight = document.body.clientHeight; sWidth = document.body.scrollWidth; sHeight = document.body.scrollHeight; sLeft = document.body.scrollLeft; sTop = document.body.scrollTop; } else { //document.compatMode == "CSS1Compat" cWidth = document.documentElement.clientWidth; cHeight = document.documentElement.clientHeight; sWidth = document.documentElement.scrollWidth; sHeight = document.documentElement.scrollHeight; sLeft = document.documentElement.scrollLeft == 0 ? document.body.scrollLeft : document.documentElement.scrollLeft; sTop = document.documentElement.scrollTop == 0 ? document.body.scrollTop : document.documentElement.scrollTop; }
(以上代码兼容目前流行的全部浏览器,包括:IE、Firefox、Safari、Opera、Chrome)
// JavaScript Document var persistclose=0 //set to 0 or 1. 1 means once the bar is manually closed, it will remain closed for browser session var startX = 3 //set x offset of bar in pixels var startY = 150 //set y offset of bar in pixels var verticalpos="fromtop" //enter "fromtop" or "frombottom" function iecompattest(){ return (document.compatMode && document.compatMode!="BackCompat")? document.documentElement : document.body; } function get_cookie(Name) { var search = Name + "="; var returnvalue = ""; if (document.cookie.length > 0) { offset = document.cookie.indexOf(search); if (offset != -1) { offset += search.length; end = document.cookie.indexOf(";", offset); if (end == -1) end = document.cookie.length; returnvalue=unescape(document.cookie.substring(offset, end)); } } return returnvalue; } /*-- function hidebar(){ if (persistclose) document.cookie="remainclosed=1"; document.getElementById("M").style.display="none"; document.getElementById("show_M").style.display="block"; } function showbar(){ if(persistclose==0) document.cookie="remainclosed=0"; document.getElementById("M").style.display="block"; document.getElementById("show_M").style.display="none"; } --*/ function staticbar(){ barheight=document.getElementById("float_qq").offsetHeight var ns = (navigator.appName.indexOf("Netscape") != -1) || window.opera; var d = document; function ml(id){ var el=d.getElementById(id); if (!persistclose || persistclose && get_cookie("remainclosed")=="") el.style.visibility="visible" if(d.layers)el.style=el; el.sP=function(x,y){this.style.left=x+"px";this.style.top=y+"px";}; el.x = startX; if (verticalpos=="fromtop") el.y = startY; else{ el.y = ns ? pageYOffset + innerHeight : iecompattest().scrollTop + iecompattest().clientHeight; el.y -= startY; } return el; } window.stayTopLeft=function(){ if (verticalpos=="fromtop"){ var pY = ns ? pageYOffset : iecompattest().scrollTop; ftlObj.y += (pY + startY - ftlObj.y)/8; } else{ var pY = ns ? pageYOffset + innerHeight - barheight: iecompattest().scrollTop + iecompattest().clientHeight - barheight; ftlObj.y += (pY - startY - ftlObj.y)/8; } ftlObj.sP(ftlObj.x, ftlObj.y); setTimeout("stayTopLeft()", 10); } ftlObj = ml("float_qq"); stayTopLeft(); } if (window.addEventListener) window.addEventListener("load", staticbar, false); else if (window.attachEvent) window.attachEvent("onload", staticbar); else if (document.getElementById) window.onload=staticbar;
转自http://www.cnblogs.com/fullhouse/archive/2012/01/17/2324706.html