试图理解为什么元兼容性标记解决了jQuery错误

我正在寻找一个解释,为什么一个特定的修复工作,所以我可以更好地理解正在发生的机制.

我有一个ASP.NET MVC 5应用程序; “一切都工作得很好”(TM),直到我允许NuGet更新jQuery包.

然后,当我尝试在IE 10中运行webapp时,我开始收到错误消息/异常：

Unhandled exception at line 3398,column 4 in http://localhost:53242/Scripts/jquery-2.1.0.js

0x800a01b6 - JavaScript runtime error: Object doesn't support property or method 'addEventListener'

Unhandled exception at line 7,column 38 in http://localhost:53242/Scripts/bootstrap.js

0x800a139e - JavaScript runtime error: Bootstrap requires jQuery

我无法使用Firefox和Chrome重新创建.当我在这些浏览器中打开页面时,Firefox 27和Chrome 31都没有抛出这些错误.

这是jquery-2.1.0.js的相关部分

jQuery.ready.promise = function( obj ) {
    if ( !readyList ) {

        readyList = jQuery.Deferred();

        // Catch cases where $(document).ready() is called after the browser event has already occurred.
        // we once tried to use readyState "interactive" here,but it caused issues like the one
        // discovered by ChrisS here: http://bugs.jquery.com/ticket/12282#comment:15
        if ( document.readyState === "complete" ) {
            // Handle it asynchronously to allow scripts the opportunity to delay ready
            setTimeout( jQuery.ready );

        } else {

            // Use the handy event callback
            document.addEventListener( "DOMContentLoaded",completed,false );  //This is line 3398

            // A fallback to window.onload,that will always work
            window.addEventListener( "load",false );
        }
    }
    return readyList.promise( obj );
};

我找到的修复是添加此行