解决HTML5布局，兼容IE问题

当我们使用h5的新标签,header,footer,aside,section,article...时，会遇到低版本IE不兼容问题，如下图：

解决方案：引入如下JS代码，即可

（这里我就直接放源码了，大家可自行拷贝成JS文件即可使用）

/*! HTML5 Shiv v3.6.1 | @afarkas @jdalton @jon_neal @rem | MIT/GPL2 Licensed */
;(function(window, document) {
/*jshint evil:true */
  /** Preset options */
  var options = window.html5 || {};

  /** Used to skip problem elements */
  var reSkip = /^<|^(?:button|map|select|textarea|object|iframe|option|optgroup)$/i;

  /** Not all elements can be cloned in IE **/
  var saveClones = /^(?:a|b|code|div|fieldset|h1|h2|h3|h4|h5|h6|i|label|li|ol|p|q|span|strong|style|table|tbody|td|th|tr|ul)$/i;

  /** Detect whether the browser supports default html5 styles */
  var supportsHtml5Styles;

  /** Name of the expando, to work with multiple documents or to re-shiv one document */
  var expando = '_html5shiv';

  /** The id for the the documents expando */
  var expanID = ;

  /** Cached data for each document */
  var expandoData = {};

  /** Detect whether the browser supports unknown elements */
  var supportsUnknownElements;

  (function() {
    try {
        var a = document.createElement('a');
        a.innerHTML = '<xyz></xyz>';
        //if the hidden property is implemented we can assume, that the browser supports basic HTML5 Styles
        supportsHtml5Styles = ('hidden' in a);

        supportsUnknownElements = a.childNodes.length ==  || (function() {
          // assign a false positive if unable to shiv
          (document.createElement)('a');
          var frag = document.createDocumentFragment();
          return (
            typeof frag.cloneNode == 'undefined' ||
            typeof frag.createDocumentFragment == 'undefined' ||
            typeof frag.createElement == 'undefined'
          );
        }());
    } catch(e) {
      supportsHtml5Styles = true;
      supportsUnknownElements = true;
    }

  }());

  /*--------------------------------------------------------------------------*/

  /**
   * Creates a style sheet with the given CSS text and adds it to the document.
   * @private
   * @param {Document} ownerDocument The document.
   * @param {String} cssText The CSS text.
   * @returns {StyleSheet} The style element.
   */
  function addStyleSheet(ownerDocument, cssText) {
    var p = ownerDocument.createElement('p'),
        parent = ownerDocument.getElementsByTagName('head')[] || ownerDocument.documentElement;

    p.innerHTML = 'x<style>' + cssText + '</style>';
    return parent.insertBefore(p.lastChild, parent.firstChild);
  }

  /**
   * Returns the value of `html5.elements` as an array.
   * @private
   * @returns {Array} An array of shived element node names.
   */
  function getElements() {
    var elements = html5.elements;
    return typeof elements == 'string' ? elements.split(' ') : elements;
  }

    /**
   * Returns the data associated to the given document
   * @private
   * @param {Document} ownerDocument The document.
   * @returns {Object} An object of data.
   */
  function getExpandoData(ownerDocument) {
    var data = expandoData[ownerDocument[expando]];
    if (!data) {
        data = {};
        expanID++;
        ownerDocument[expando] = expanID;
        expandoData[expanID] = data;
    }
    return data;
  }

  /**
   * returns a shived element for the given nodeName and document
   * @memberOf html5
   * @param {String} nodeName name of the element
   * @param {Document} ownerDocument The context document.
   * @returns {Object} The shived element.
   */
  function createElement(nodeName, ownerDocument, data){
    if (!ownerDocument) {
        ownerDocument = document;
    }
    if(supportsUnknownElements){
        return ownerDocument.createElement(nodeName);
    }
    if (!data) {
        data = getExpandoData(ownerDocument);
    }
    var node;

    if (data.cache[nodeName]) {
        node = data.cache[nodeName].cloneNode();
    } else if (saveClones.test(nodeName)) {
        node = (data.cache[nodeName] = data.createElem(nodeName)).cloneNode();
    } else {
        node = data.createElem(nodeName);
    }

    // Avoid adding some elements to fragments in IE < 9 because
    // * Attributes like `name` or `type` cannot be set/changed once an element
    //   is inserted into a document/fragment
    // * Link elements with `src` attributes that are inaccessible, as with
    //   a 403 response, will cause the tab/window to crash
    // * Script elements appended to fragments will execute when their `src`
    //   or `text` property is set
    return node.canHaveChildren && !reSkip.test(nodeName) ? data.frag.appendChild(node) : node;
  }

  /**
   * returns a shived DocumentFragment for the given document
   * @memberOf html5
   * @param {Document} ownerDocument The context document.
   * @returns {Object} The shived DocumentFragment.
   */
  function createDocumentFragment(ownerDocument, data){
    if (!ownerDocument) {
        ownerDocument = document;
    }
    if(supportsUnknownElements){
        return ownerDocument.createDocumentFragment();
    }
    data = data || getExpandoData(ownerDocument);
    var clone = data.frag.cloneNode(),
        i = ,
        elems = getElements(),
        l = elems.length;
    for(;i<l;i++){
        clone.createElement(elems[i]);
    }
    return clone;
  }

  /**
   * Shivs the `createElement` and `createDocumentFragment` methods of the document.
   * @private
   * @param {Document|DocumentFragment} ownerDocument The document.
   * @param {Object} data of the document.
   */
  function shivMethods(ownerDocument, data) {
    if (!data.cache) {
        data.cache = {};
        data.createElem = ownerDocument.createElement;
        data.createFrag = ownerDocument.createDocumentFragment;
        data.frag = data.createFrag();
    }

    ownerDocument.createElement = function(nodeName) {
      //abort shiv
      if (!html5.shivMethods) {
          return data.createElem(nodeName);
      }
      return createElement(nodeName, ownerDocument, data);
    };

    ownerDocument.createDocumentFragment = Function('h,f', 'return function(){' +
      'var n=f.cloneNode(),c=n.createElement;' +
      'h.shivMethods&&(' +
        // unroll the `createElement` calls
        getElements().join().replace(/\w+/g, function(nodeName) {
          data.createElem(nodeName);
          data.frag.createElement(nodeName);
          return 'c("' + nodeName + '")';
        }) +
      ');return n}'
    )(html5, data.frag);
  }

  /*--------------------------------------------------------------------------*/

  /**
   * Shivs the given document.
   * @memberOf html5
   * @param {Document} ownerDocument The document to shiv.
   * @returns {Document} The shived document.
   */
  function shivDocument(ownerDocument) {
    if (!ownerDocument) {
        ownerDocument = document;
    }
    var data = getExpandoData(ownerDocument);

    if (html5.shivCSS && !supportsHtml5Styles && !data.hasCSS) {
      data.hasCSS = !!addStyleSheet(ownerDocument,
        // corrects block display not defined in IE6/7/8/9
        'article,aside,figcaption,figure,footer,header,hgroup,nav,section{display:block}' +
        // adds styling not present in IE6/7/8/9
        'mark{background:#FF0;color:#000}'
      );
    }
    if (!supportsUnknownElements) {
      shivMethods(ownerDocument, data);
    }
    return ownerDocument;
  }

  /*--------------------------------------------------------------------------*/

  /**
   * The `html5` object is exposed so that more elements can be shived and
   * existing shiving can be detected on iframes.
   * @type Object
   * @example
   *
   * // options can be changed before the script is included
   * html5 = { 'elements': 'mark section', 'shivCSS': false, 'shivMethods': false };
   */
  var html5 = {

    /**
     * An array or space separated string of node names of the elements to shiv.
     * @memberOf html5
     * @type Array|String
     */
    'elements': options.elements || 'abbr article aside audio bdi canvas data datalist details figcaption figure footer header hgroup mark meter nav output progress section summary time video',

    /**
     * A flag to indicate that the HTML5 style sheet should be inserted.
     * @memberOf html5
     * @type Boolean
     */
    'shivCSS': (options.shivCSS !== false),

    /**
     * Is equal to true if a browser supports creating unknown/HTML5 elements
     * @memberOf html5
     * @type boolean
     */
    'supportsUnknownElements': supportsUnknownElements,

    /**
     * A flag to indicate that the document's `createElement` and `createDocumentFragment`
     * methods should be overwritten.
     * @memberOf html5
     * @type Boolean
     */
    'shivMethods': (options.shivMethods !== false),

    /**
     * A string to describe the type of `html5` object ("default" or "default print").
     * @memberOf html5
     * @type String
     */
    'type': 'default',

    // shivs the document according to the specified `html5` object options
    'shivDocument': shivDocument,

    //creates a shived element
    createElement: createElement,

    //creates a shived documentFragment
    createDocumentFragment: createDocumentFragment
  };

  /*--------------------------------------------------------------------------*/

  // expose html5
  window.html5 = html5;

  // shiv the document
  shivDocument(document);

}(this, document));