html控件

checkbox

val = "<li class='layer'><label><input type='checkbox' checked name='layers' class='layerSelect' id='" + layers_name_list[i] + "'><span>" + layers_name_list[i] + "</span></label></li>"

items = document.getElementsByName("layers");

判断是否选中：items[0].checked;

设置选中：items[0].checked = true;

整形变字符串：String()

字符串变整形：Number()