js生成验证码并直接在前端判断_javascript技巧

 
 

 var code; //在全局 定义验证码
 var code2; //在全局 定义验证码
 function createCode() {
 code = "";
 var checkCode = document.getElementById("checkCode");
 function RndNum(n) {
 var rnd = "";
 for (var i = 0; i < n; i++)
 rnd += Math.floor(Math.random() * 10);
 return rnd;
 }

 var num = RndNum(2);
 var num2 = RndNum(2);

 code = num + "+" + num2 + "=";
 code2 = parseInt(num) + parseInt(num2)

 if (checkCode) {
 checkCode.className = "code";
 checkCode.value = code;
 }

 }