var splitArrays = {};
for(var i = 0; i < All_array.length; ++i){
    var firstChar = All_array[i].substr(0,1).toUpperCase();
    if(!splitArrays[firstChar + '_array'])
        splitArrays[firstChar + '_array'] = [];
    splitArrays[firstChar + '_array'].push(All_array[i]);
}

这将获取All_array中的每个元素，并将它们放入包含由All_array中的元素的第一个字母索引的数组的对象，如下所示:

This will take every element in All_array and put them into an object containing the arrays indexed by the first letter of the elements in All_array, like this:

splitArrays.A_array = ['Abcd','Anej','Aali']

等...

这是一个小提琴: http://jsfiddle.net/svjJ9/