运算表达式：常见运算法 ：＋ — X ÷Js中常用符： ＋ — * /加法运算： var weight =65;
weight=weight+10;
alert(weight); 减法运算： var dogName="zahngsan";
dogName=dogName+"zhangsa"; 取余运算： %表示 var num1 =10;
var num
function loadStyles(url) {
var link = document.createElement("link");
link.rel = "stylesheet";
link.type = "text/css";
link.href = url;
var head = document.getElemen
