js临时笔记

字符转ascii码：用charCodeAt();
ascii码转字符：用fromCharCode();

看一个小例子

<script>
str="A";
code = str.charCodeAt();
str2 = String.fromCharCode(code);
str3 = String.fromCharCode(0x60+26);

document.write(code+'<br />');
document.write(str2+'<br />');
document.write(str3);
</script>

输出：

65
A
z

遍历整个字符串，然后一个字符一个字符判断，asc码小于256的都是单字节比如：var   v   =   "中国abc";var   len   =   0;for(i=0;i<v.length;i++){if(v.charCodeAt(i)>256){len   +=   2;}else{len++;}}alert("长度是"+len);