jquery 遍历 id 或 class

html 中有个ID [php] <span class="total">1</span> <span class="total">2</span> <span class="total">3</span> <span class="total">4</span> [/php] 利用jquery遍历id 获取累加和: [php] $a=0; $(".total").each(function(){ $a += Number($(this).text()); }); alert($a); [/php]