javascript - IE8 中的 JavaScript 错误，但 IE 10 中没有

Question

我正在使用 IE 10 并使用 ExtJs 4.1 开发了一个树面板。当我在 IE 10 中运行应用程序时，一切正常，但是一旦我切换到 IE 8（在 IE 10 中使用 IE 开发人员工具栏浏览器模式选项），我就会收到 JavaScript 错误。到目前为止，我从未见过 EXTJ 出现这种不一致的行为。

请使用以下小提琴重现该问题。

http://jsfiddle.net/BYqRN/20/

Ext.create('Ext.tree.Panel', {
    title: 'Simple Tree',
    renderTo: Ext.getBody(),
    width: 400,
    height: 400,
    store: {
        root: {
            expanded: true,
            children: [{
                checked: false,
                text: "1 detention",
                expanded: true,
                children: [{
                    checked: false,
                    text: '1.1 foo',
                    leaf: false,
                    children: [{
                        checked: false,
                        text: "1.1.1 India",
                        expanded: true
                    }, {
                        checked: false,
                        text: "1.1.2 Singapore",
                        expanded: true
                    }, {
                        checked: false,
                        text: "1.1.3 USA",
                        expanded: true
                    }]
                }, {
                    checked: false,
                    text: '1.2 bar',
                    leaf: true
                }]
            }, {
                checked: false,
                text: "2 homework",
                expanded: true,
                children: [{
                    checked: false,
                    text: "2.1 book report",
                    leaf: true
                }, {
                    checked: false,
                    text: "2.2 algebra",
                    expanded: true,
                    children: [{
                        checked: false,
                        text: "2.2.1 buy lottery tickets",
                        leaf: true
                    }, {
                        checked: false,
                        text: "2.2.2 buy lottery tickets 2",
                        leaf: true
                    }]
                }, {
                    checked: false,
                    text: "2.3 English report",
                    leaf: true
                }]
            }, {
                checked: false,
                text: "3 buy lottery tickets",
                leaf: true
            }]
        }
    },
    rootVisible: false,
    disableSelection: true,
    //selModel: {mode: 'SIMPLE'},
    listeners: {
        checkchange: function (record, checked, opts) {
            if (!checked) return;
            var parentNode = record.parentNode;

            // Deselect children
            function deselectChildren(record) {
                record.eachChild(function (record) {
                    record.set('checked', false);
                    deselectChildren(record);
                });
            }
            deselectChildren(record);

            // See if all siblings are selected now
            var allSiblingSelected = false;
            if (parentNode) {
                allSiblingSelected = parentNode.childNodes.reduce(function (previous, node) {
                    return previous && node.get('checked');
                }, true);
            }

            if (allSiblingSelected) {
                parentNode.set('checked', true);
                // Apparently won't fire on its own
                this.fireEvent('checkchange', parentNode, true, opts);
            }

            // Deselect ancestors
            else {
                while (parentNode) {
                    parentNode.set('checked', false);
                    parentNode = parentNode.parentNode;
                }
            }
        }
    }
});

我还附加了我在 IE 8 中遇到的错误

请提供您的建议。

谢谢

Answer 1

reduce旧浏览器不支持，它在 ECMA Script 5 中实现检查https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/Reduce

您可以为旧浏览器定义功能：

if ('function' !== typeof Array.prototype.reduce) {
  Array.prototype.reduce = function(callback, opt_initialValue){
    'use strict';
    if (null === this || 'undefined' === typeof this) {
      // At the moment all modern browsers, that support strict mode, have
      // native implementation of Array.prototype.reduce. For instance, IE8
      // does not support strict mode, so this check is actually useless.
      throw new TypeError(
          'Array.prototype.reduce called on null or undefined');
    }
    if ('function' !== typeof callback) {
      throw new TypeError(callback + ' is not a function');
    }
    var index = 0, length = this.length >>> 0, value, isValueSet = false;
    if (1 < arguments.length) {
      value = opt_initialValue;
      isValueSet = true;
    }
    for ( ; length > index; ++index) {
      if (!this.hasOwnProperty(index)) continue;
      if (isValueSet) {
        value = callback(value, this[index], index, this);
      } else {
        value = this[index];
        isValueSet = true;
      }
    }
    if (!isValueSet) {
      throw new TypeError('Reduce of empty array with no initial value');
    }
    return value;
  };
}