jquery中的数组迭代

Question

这是我的代码

$('select.more-search').each(function(i, e){ 
    more_srch[i] = $(this).attr('name'); 
    $('#'+more_srch[i]+' :selected').each(function(j, selected){ 
      more_sel[i][j] = $(selected).val(); 
    });
});

在控制台显示错误为TypeError: more_sel[i] is undefined

如何消除这个错误?

Answer 1

需要先将more_sel[i]初始化为空数组，然后才能对元素进行赋值。

$('select.more-search').each(function(i, e){ 
    more_srch[i] = $(this).attr('name'); 
    more_sel[i] = [];
    $('#'+more_srch[i]+' :selected').each(function(j, selected){ 
      more_sel[i][j] = $(selected).val(); 
    });
});

不用.each()，可以用.map():

 $('select.more-search').each(function(i, e){ 
    more_srch[i] = $(this).attr('name'); 
    more_sel[i] = $('#'+more_srch[i]+' :selected').map(function(j, selected){ 
      return $(selected).val(); 
    }).get(); // use .get() to turn returned jQuery object into normal array
});