【笔记】11.21 前端的兼容性

1.案例1

 问题原因:子级的宽度会撑开父级设置好的宽度

 解决方案:将子级的宽度设置小于父级元素的宽度

       盒模型一定要计算准确,否则在IE下会出现问题


2.案例2

 问题原因:元素浮动时,如果元素需要宽度撑开,需要给里面的块元素添加浮动才行

 (注意:内容是块元素才会有此问题)

 解决方案:给里面的内容加上浮动


3.案例3

 问题原因:在IE6/7下,元素通过浮动排在同一行,如果其中一个元素没有设置浮动,则会出现间隙

 解决方案:给这行元素都加浮动



4.案例4

 问题原因:在IE6下元素的高度如果小于19px,会被当做19p处理

 解决方案:设置overflow:hidden;


5.案例5

 问题原因:IE6不支持dotted和dashed边框


6.案例6

问题原因:当父级设置了边框后,子级的margin依然无效

  解决方案:设置zoom:1(设置内容加载时的初始倍率)

 触发IE6的hasLayout最常用的手段


7.案例7

 问题原因:在IE6下双边距的BUG

块元素有浮动并且横向有margind的时候,横向的margin会扩大两倍,形成双边距;

  解决方案:设置display:inline;



8.问题原因:margin-left一行中最左侧的第一个元素具有双边距

                     mragin-right一行中最右侧的第一个元素具有双边距

                     解决方案:设置display:inline;


9.问题原因:在IE6/7下,li本身没有浮动,li里面的内容有浮动,li下会产生间隙

  解决方案:1)给li加浮动(会对标准服务器产生影响)

                     2)给li加vertical-align


10.基于案例9,同时触发最小高度和li的问题

问题原因:在IE6下,最小高度的BUG和li的间隙共存的时候,使用vertical-align是无效的。

解决方法:给li同时设置overflow:hidden和flow:left

(这种情况下标准游览器是会出现问题的,一般给li设置固定宽度可以解决)






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11.案例11

问题原因:IE6下的文字溢出BUG

子元素的宽度和父级元素的宽度如果相差小于3px,两个浮动元素中间有注释或者内联元 素的时候,就会出现文字溢出,内联元素越多,溢出越多

解决方法:用块标签把注释或内联元素包裹起来





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李先生真帅




 12.案例12

    问题原因:当一行子元素的宽度跟父级元素的宽度相差超过3px,或者子元素元素不满行的时候,                       最后一行的子级元素的margin-bottom会失效

     解决方案:计算好总数






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13.案例13


   问题原因:当浮动元素和绝对定位元素是兄弟关系时,绝对定位会失效


   解决方案:套多一层div,不让起成兄弟关系






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    14.案例14


       问题原因:子元素有相对定位,父级没有相对定位的时候,父级设置overflow包不住子级元素


       解决方案:给父级元素也设置相对定位






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    15.案例十五


      问题原因:如果绝对定位的父级宽

    和高是奇数的时候,子级元素会有1px的偏差


      解决方案:找美工改为偶数





    Document








    16.方案16

      问题原因:IE6中不存在固定定位,只有绝对定位

      解决方案:只能通过JS模拟该效果



    17.案例17

    问题原因:IE中不认识opacity

    解决方案:filter(opacity=50)



    18.案例18

    问题原因:输入型表单控件上下会有1px的间隙

    解决方案:给input加浮动






    Document









    19.案例19







    Document







    需要加入的JS文件


    /**
    * DD_belatedPNG: Adds IE6 support: PNG images for CSS background-image and HTML .
    * Author: Drew Diller
    * Email: [email protected]
    * URL: http://www.dillerdesign.com/experiment/DD_belatedPNG/
    * Version: 0.0.8a
    * Licensed under the MIT License: http://dillerdesign.com/experiment/DD_belatedPNG/#license
    *
    * Example usage:
    * DD_belatedPNG.fix('.png_bg'); // argument is a CSS selector
    * DD_belatedPNG.fixPng( someNode ); // argument is an HTMLDomElement
    **/

    /*
    PLEASE READ:
    Absolutely everything in this script is SILLY. I know this. IE's rendering of certain pixels doesn't make sense, so neither does this code!
    */

    var DD_belatedPNG = {
    ns: 'DD_belatedPNG',
    imgSize: {},
    delay: 10,
    nodesFixed: 0,
    createVmlNameSpace: function () { /* enable VML */
    if (document.namespaces && !document.namespaces[this.ns]) {
    document.namespaces.add(this.ns, 'urn:schemas-microsoft-com:vml');
    }
    },
    createVmlStyleSheet: function () { /* style VML, enable behaviors */
    /*
    Just in case lots of other developers have added
    lots of other stylesheets using document.createStyleSheet
    and hit the 31-limit mark, let's not use that method!
    further reading: http://msdn.microsoft.com/en-us/library/ms531194(VS.85).aspx
    */
    var screenStyleSheet, printStyleSheet;
    screenStyleSheet = document.createElement('style');
    screenStyleSheet.setAttribute('media', 'screen');
    document.documentElement.firstChild.insertBefore(screenStyleSheet, document.documentElement.firstChild.firstChild);
    if (screenStyleSheet.styleSheet) {
    screenStyleSheet = screenStyleSheet.styleSheet;
    screenStyleSheet.addRule(this.ns + '\\:*', '{behavior:url(#default#VML)}');
    screenStyleSheet.addRule(this.ns + '\\:shape', 'position:absolute;');
    screenStyleSheet.addRule('img.' + this.ns + '_sizeFinder', 'behavior:none; border:none; position:absolute; z-index:-1; top:-10000px; visibility:hidden;'); /* large negative top value for avoiding vertical scrollbars for large images, suggested by James O'Brien, http://www.thanatopsic.org/hendrik/ */
    this.screenStyleSheet = screenStyleSheet;

    /* Add a print-media stylesheet, for preventing VML artifacts from showing up in print (including preview). */
    /* Thanks to Rémi Prévost for automating this! */
    printStyleSheet = document.createElement('style');
    printStyleSheet.setAttribute('media', 'print');
    document.documentElement.firstChild.insertBefore(printStyleSheet, document.documentElement.firstChild.firstChild);
    printStyleSheet = printStyleSheet.styleSheet;
    printStyleSheet.addRule(this.ns + '\\:*', '{display: none !important;}');
    printStyleSheet.addRule('img.' + this.ns + '_sizeFinder', '{display: none !important;}');
    }
    },
    readPropertyChange: function () {
    var el, display, v;
    el = event.srcElement;
    if (!el.vmlInitiated) {
    return;
    }
    if (event.propertyName.search('background') != -1 || event.propertyName.search('border') != -1) {
    DD_belatedPNG.applyVML(el);
    }
    if (event.propertyName == 'style.display') {
    display = (el.currentStyle.display == 'none') ? 'none' : 'block';
    for (v in el.vml) {
    if (el.vml.hasOwnProperty(v)) {
    el.vml[v].shape.style.display = display;
    }
    }
    }
    if (event.propertyName.search('filter') != -1) {
    DD_belatedPNG.vmlOpacity(el);
    }
    },
    vmlOpacity: function (el) {
    if (el.currentStyle.filter.search('lpha') != -1) {
    var trans = el.currentStyle.filter;
    trans = parseInt(trans.substring(trans.lastIndexOf('=')+1, trans.lastIndexOf(')')), 10)/100;
    el.vml.color.shape.style.filter = el.currentStyle.filter; /* complete guesswork */
    el.vml.image.fill.opacity = trans; /* complete guesswork */
    }
    },
    handlePseudoHover: function (el) {
    setTimeout(function () { /* wouldn't work as intended without setTimeout */
    DD_belatedPNG.applyVML(el);
    }, 1);
    },
    /**
    * This is the method to use in a document.
    * @param {String} selector - REQUIRED - a CSS selector, such as '#doc .container'
    **/
    fix: function (selector) {
    if (this.screenStyleSheet) {
    var selectors, i;
    selectors = selector.split(','); /* multiple selectors supported, no need for multiple calls to this anymore */
    for (i=0; i this.screenStyleSheet.addRule(selectors[i], 'behavior:expression(DD_belatedPNG.fixPng(this))'); /* seems to execute the function without adding it to the stylesheet - interesting... */
    }
    }
    },
    applyVML: function (el) {
    el.runtimeStyle.cssText = '';
    this.vmlFill(el);
    this.vmlOffsets(el);
    this.vmlOpacity(el);
    if (el.isImg) {
    this.copyImageBorders(el);
    }
    },
    attachHandlers: function (el) {
    var self, handlers, handler, moreForAs, a, h;
    self = this;
    handlers = {resize: 'vmlOffsets', move: 'vmlOffsets'};
    if (el.nodeName == 'A') {
    moreForAs = {mouseleave: 'handlePseudoHover', mouseenter: 'handlePseudoHover', focus: 'handlePseudoHover', blur: 'handlePseudoHover'};
    for (a in moreForAs) {
    if (moreForAs.hasOwnProperty(a)) {
    handlers[a] = moreForAs[a];
    }
    }
    }
    for (h in handlers) {
    if (handlers.hasOwnProperty(h)) {
    handler = function () {
    self[handlers[h]](el);
    };
    el.attachEvent('on' + h, handler);
    }
    }
    el.attachEvent('onpropertychange', this.readPropertyChange);
    },
    giveLayout: function (el) {
    el.style.zoom = 1;
    if (el.currentStyle.position == 'static') {
    el.style.position = 'relative';
    }
    },
    copyImageBorders: function (el) {
    var styles, s;
    styles = {'borderStyle':true, 'borderWidth':true, 'borderColor':true};
    for (s in styles) {
    if (styles.hasOwnProperty(s)) {
    el.vml.color.shape.style[s] = el.currentStyle[s];
    }
    }
    },
    vmlFill: function (el) {
    if (!el.currentStyle) {
    return;
    } else {
    var elStyle, noImg, lib, v, img, imgLoaded;
    elStyle = el.currentStyle;
    }
    for (v in el.vml) {
    if (el.vml.hasOwnProperty(v)) {
    el.vml[v].shape.style.zIndex = elStyle.zIndex;
    }
    }
    el.runtimeStyle.backgroundColor = '';
    el.runtimeStyle.backgroundImage = '';
    noImg = true;
    if (elStyle.backgroundImage != 'none' || el.isImg) {
    if (!el.isImg) {
    el.vmlBg = elStyle.backgroundImage;
    el.vmlBg = el.vmlBg.substr(5, el.vmlBg.lastIndexOf('")')-5);
    }
    else {
    el.vmlBg = el.src;
    }
    lib = this;
    if (!lib.imgSize[el.vmlBg]) { /* determine size of loaded image */
    img = document.createElement('img');
    lib.imgSize[el.vmlBg] = img;
    img.className = lib.ns + '_sizeFinder';
    img.runtimeStyle.cssText = 'behavior:none; position:absolute; left:-10000px; top:-10000px; border:none; margin:0; padding:0;'; /* make sure to set behavior to none to prevent accidental matching of the helper elements! */
    imgLoaded = function () {
    this.width = this.offsetWidth; /* weird cache-busting requirement! */
    this.height = this.offsetHeight;
    lib.vmlOffsets(el);
    };
    img.attachEvent('onload', imgLoaded);
    img.src = el.vmlBg;
    img.removeAttribute('width');
    img.removeAttribute('height');
    document.body.insertBefore(img, document.body.firstChild);
    }
    el.vml.image.fill.src = el.vmlBg;
    noImg = false;
    }
    el.vml.image.fill.on = !noImg;
    el.vml.image.fill.color = 'none';
    el.vml.color.shape.style.backgroundColor = elStyle.backgroundColor;
    el.runtimeStyle.backgroundImage = 'none';
    el.runtimeStyle.backgroundColor = 'transparent';
    },
    /* IE can't figure out what do when the offsetLeft and the clientLeft add up to 1, and the VML ends up getting fuzzy... so we have to push/enlarge things by 1 pixel and then clip off the excess */
    vmlOffsets: function (el) {
    var thisStyle, size, fudge, makeVisible, bg, bgR, dC, altC, b, c, v;
    thisStyle = el.currentStyle;
    size = {'W':el.clientWidth+1, 'H':el.clientHeight+1, 'w':this.imgSize[el.vmlBg].width, 'h':this.imgSize[el.vmlBg].height, 'L':el.offsetLeft, 'T':el.offsetTop, 'bLW':el.clientLeft, 'bTW':el.clientTop};
    fudge = (size.L + size.bLW == 1) ? 1 : 0;
    /* vml shape, left, top, width, height, origin */
    makeVisible = function (vml, l, t, w, h, o) {
    vml.coordsize = w+','+h;
    vml.coordorigin = o+','+o;
    vml.path = 'm0,0l'+w+',0l'+w+','+h+'l0,'+h+' xe';
    vml.style.width = w + 'px';
    vml.style.height = h + 'px';
    vml.style.left = l + 'px';
    vml.style.top = t + 'px';
    };
    makeVisible(el.vml.color.shape, (size.L + (el.isImg ? 0 : size.bLW)), (size.T + (el.isImg ? 0 : size.bTW)), (size.W-1), (size.H-1), 0);
    makeVisible(el.vml.image.shape, (size.L + size.bLW), (size.T + size.bTW), (size.W), (size.H), 1 );
    bg = {'X':0, 'Y':0};
    if (el.isImg) {
    bg.X = parseInt(thisStyle.paddingLeft, 10) + 1;
    bg.Y = parseInt(thisStyle.paddingTop, 10) + 1;
    }
    else {
    for (b in bg) {
    if (bg.hasOwnProperty(b)) {
    this.figurePercentage(bg, size, b, thisStyle['backgroundPosition'+b]);
    }
    }
    }
    el.vml.image.fill.position = (bg.X/size.W) + ',' + (bg.Y/size.H);
    bgR = thisStyle.backgroundRepeat;
    dC = {'T':1, 'R':size.W+fudge, 'B':size.H, 'L':1+fudge}; /* these are defaults for repeat of any kind */
    altC = { 'X': {'b1': 'L', 'b2': 'R', 'd': 'W'}, 'Y': {'b1': 'T', 'b2': 'B', 'd': 'H'} };
    if (bgR != 'repeat' || el.isImg) {
    c = {'T':(bg.Y), 'R':(bg.X+size.w), 'B':(bg.Y+size.h), 'L':(bg.X)}; /* these are defaults for no-repeat - clips down to the image location */
    if (bgR.search('repeat-') != -1) { /* now let's revert to dC for repeat-x or repeat-y */
    v = bgR.split('repeat-')[1].toUpperCase();
    c[altC[v].b1] = 1;
    c[altC[v].b2] = size[altC[v].d];
    }
    if (c.B > size.H) {
    c.B = size.H;
    }
    el.vml.image.shape.style.clip = 'rect('+c.T+'px '+(c.R+fudge)+'px '+c.B+'px '+(c.L+fudge)+'px)';
    }
    else {
    el.vml.image.shape.style.clip = 'rect('+dC.T+'px '+dC.R+'px '+dC.B+'px '+dC.L+'px)';
    }
    },
    figurePercentage: function (bg, size, axis, position) {
    var horizontal, fraction;
    fraction = true;
    horizontal = (axis == 'X');
    switch(position) {
    case 'left':
    case 'top':
    bg[axis] = 0;
    break;
    case 'center':
    bg[axis] = 0.5;
    break;
    case 'right':
    case 'bottom':
    bg[axis] = 1;
    break;
    default:
    if (position.search('%') != -1) {
    bg[axis] = parseInt(position, 10) / 100;
    }
    else {
    fraction = false;
    }
    }
    bg[axis] = Math.ceil( fraction ? ( (size[horizontal?'W': 'H'] * bg[axis]) - (size[horizontal?'w': 'h'] * bg[axis]) ) : parseInt(position, 10) );
    if (bg[axis] % 2 === 0) {
    bg[axis]++;
    }
    return bg[axis];
    },
    fixPng: function (el) {
    el.style.behavior = 'none';
    var lib, els, nodeStr, v, e;
    if (el.nodeName == 'BODY' || el.nodeName == 'TD' || el.nodeName == 'TR') { /* elements not supported yet */
    return;
    }
    el.isImg = false;
    if (el.nodeName == 'IMG') {
    if(el.src.toLowerCase().search(/\.png$/) != -1) {
    el.isImg = true;
    el.style.visibility = 'hidden';
    }
    else {
    return;
    }
    }
    else if (el.currentStyle.backgroundImage.toLowerCase().search('.png') == -1) {
    return;
    }
    lib = DD_belatedPNG;
    el.vml = {color: {}, image: {}};
    els = {shape: {}, fill: {}};
    for (v in el.vml) {
    if (el.vml.hasOwnProperty(v)) {
    for (e in els) {
    if (els.hasOwnProperty(e)) {
    nodeStr = lib.ns + ':' + e;
    el.vml[v][e] = document.createElement(nodeStr);
    }
    }
    el.vml[v].shape.stroked = false;
    el.vml[v].shape.appendChild(el.vml[v].fill);
    el.parentNode.insertBefore(el.vml[v].shape, el);
    }
    }
    el.vml.image.shape.fillcolor = 'none'; /* Don't show blank white shapeangle when waiting for image to load. */
    el.vml.image.fill.type = 'tile'; /* Makes image show up. */
    el.vml.color.fill.on = false; /* Actually going to apply vml element's style.backgroundColor, so hide the whiteness. */
    lib.attachHandlers(el);
    lib.giveLayout(el);
    lib.giveLayout(el.offsetParent);
    el.vmlInitiated = true;
    lib.applyVML(el); /* Render! */
    }
    };
    try {
    document.execCommand("BackgroundImageCache", false, true); /* TredoSoft Multiple IE doesn't like this, so try{} it */
    } catch(r) {}
    DD_belatedPNG.createVmlNameSpace();
    DD_belatedPNG.createVmlStyleSheet();

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