js的字符串charAt()方法

//字符中的字符从左向右进行索引，由0开始，字符串中的空格也算在内

var string = "charAt find word position";
document.write("charAt find word position"+ "<br/>")
document.write("string.charAt(0) is：" + string.charAt(0) + "<br/>");
document.write("string.charAt(1) is：" + string.charAt(1) + "<br/>");
document.write("string.charAt(2) is：" + string.charAt(2) + "<br/>");
document.write("string.charAt(3) is: " + string.charAt(3) + "<br/>");
document.write("string.charAt(4) is: " + string.charAt(4) + "<br/>");
document.write("string.charAt(5) is: " + string.charAt(5) + "<br/>");
document.write("string.charAt(6) is: " + string.charAt(6) + "<br/>");
document.write("string.charAt(7) is: " + string.charAt(7) + "<br/>");
document.write("string.charAt(string.length-2) is: " + string.charAt(string.length-2) + "<br/>")
document.write("string.charAt(string.length-1) is: " + string.charAt(string.length-1) + "<br/>")

//输出结果
string.charAt(0) is：c
string.charAt(1) is：h
string.charAt(2) is：a
string.charAt(3) is: r
string.charAt(4) is: A
string.charAt(5) is: t
string.charAt(6) is: 
string.charAt(7) is: f
string.charAt(string.length-2) is: o
string.charAt(string.length-1) is: n

//返回该字符串

function findCharAt(str,n){
    var obj = String(str);      // 转化为字符串
    var pos;                    //定义变量
    pos = obj.charAt(n-1);      //查找的索引
    return pos;                 //返回字符
}
alert(findCharAt("这是第几个",1));