js 函数

var sn;
var result;
var result1;
var result2;
sn = Math.random()*100;// randow这个函数是随机取值0到1的数值；
result = Math.round(sn);//四舍五入
result1 = Math.ceil(sn);//上浮4.2到5
result2 = Math.floor(sn);//下浮4.8到4
console.log(sn);
console.log(result,result1,result2);
var str = "abc.html";
var result;
var sb;
sb = str.indexOf(".");//这个是查询 点 这个字符串在哪个下标位置 如 3
result = str.substring(sb+1,str.length+1);//输出结果 html sb+1 是查询点以后的数字 arr.length+1找的是 点 后的数组的长度
console.log(result);

var st = "adsd";
var s;
s = st.replace(/ad/,"bb");//把ad这个字符串换成bb这个字符串
console.log(s);

 

var stre = "how are you doing today";
var ss = stre.split(" ");
var fleet;
var msg = "";
for (var i = 0;i <ss.length;i++)
{
fleet = ss[i].substring(0,1);
msg += ss[i].replace(fleet,fleet.toLocaleUpperCase()) + " ";

}
console.log(msg);