arr.sort(function(a,b) {
    a = a.toLowerCase();
    b = b.toLowerCase();
    if (a == b) return 0;
    if (a > b) return 1;
    return -1;
});

用. tolowercase()规范.sort()中的case。

为了支持已接受的答案，我想补充一点，下面的函数似乎改变了原始数组中的值，以便不仅对小写进行排序，而且大写值也将被更改为小写。这对我来说是一个问题，因为即使我希望看到玛丽在玛丽旁边，我也不希望第一个值玛丽的大小写改为小写。

myArray.sort(
  function(a, b) {
    if (a.toLowerCase() < b.toLowerCase()) return -1;
    if (a.toLowerCase() > b.toLowerCase()) return 1;
    return 0;
  }
);

在我的实验中，下面的函数从接受的答案正确排序，但没有改变值。

["Foo", "bar"].sort(function (a, b) {
    return a.toLowerCase().localeCompare(b.toLowerCase());
});

如果你在努力理解以下内容，这可能会有所帮助:

var array = ["sort", "Me", "alphabetically", "But", "Ignore", "case"];
console.log('Unordered array ---', array, '------------');

array.sort(function(a,b) {
    a = a.toLowerCase();
    b = b.toLowerCase();
    console.log("Compare '" + a + "' and '" + b + "'");

    if( a == b) {
        console.log('Comparison result, 0 --- leave as is ');
        return 0;
    }
    if( a > b) {
        console.log('Comparison result, 1 --- move '+b+' to before '+a+' ');
        return 1;
    }
    console.log('Comparison result, -1 --- move '+a+' to before '+b+' ');
    return -1;


});

console.log('Ordered array ---', array, '------------');


// return logic

/***
If compareFunction(a, b) is less than 0, sort a to a lower index than b, i.e. a comes first.
If compareFunction(a, b) returns 0, leave a and b unchanged with respect to each other, but sorted with respect to all different elements. Note: the ECMAscript standard does not guarantee this behaviour, and thus not all browsers (e.g. Mozilla versions dating back to at least 2003) respect this.
If compareFunction(a, b) is greater than 0, sort b to a lower index than a.
***/

http://jsfiddle.net/ianjamieson/wmxn2ram/1/

其他答案假设数组包含字符串。我的方法更好，因为即使数组包含null、undefined或其他非字符串，它也能工作。

var notdefined;
var myarray = ['a', 'c', null, notdefined, 'nulk', 'BYE', 'nulm'];

myarray.sort(ignoreCase);

alert(JSON.stringify(myarray));    // show the result

function ignoreCase(a,b) {
    return (''+a).toUpperCase() < (''+b).toUpperCase() ? -1 : 1;
}

null将在'nulk'和'nulm'之间排序。但未定义的总是排在最后。

如果不管输入数组中元素的顺序如何，你都想保证相同的顺序，这里是一个稳定排序:

myArray.sort(function(a, b) {
    /* Storing case insensitive comparison */
    var comparison = a.toLowerCase().localeCompare(b.toLowerCase());
    /* If strings are equal in case insensitive comparison */
    if (comparison === 0) {
        /* Return case sensitive comparison instead */
        return a.localeCompare(b);
    }
    /* Otherwise return result */
    return comparison;
});