原文地址：http://www.jb51.net/article/60398.htm（我知道这不是原作者，请知道的转告我jackqqq123@sina.com）
简单版
/*
var hangstr="this is {0},{1}";
printf(hangstr,"me","guy");
//result :this is me,guy
*/
function printf() {
var num = arguments.length;
var oStr = arguments[0];
for (var i = 1; i < num; i++) {
var pattern = "\\{" + (i-1) + "\\}";
var re = new RegExp(pattern, "g");
oStr = oStr.replace(re, arguments[i]);
}
return oStr;
}
完整功能
1.%% - 返回百分号本身
2.%b - 二进制数字
3.%c - ASCII对应的字符
4.%d - 整数
5.%f - 浮点数
6.%o - 八进制数字
7.%s - 字符串
8.%x - 16进制数字 (小写字母形式)
9.%X - 16进制数字 (大写字母形式)
在 % 号和通配字符之间可用的选项包括 (比如 %.2f)：
1.+????? (强制在数字前面显示 + 和 - 符号作为正负数标记。缺省情况下只有负数才显示 - 符号)
2.-????? (变量左对齐)
3.0????? (使用0作为右对齐的填充字符)
4.[0-9]? (设置变量的最小宽度)
5..[0-9] (设置浮点数精度或字符串的长度)
/*
*/
/**
*
* Javascript sprintf
* http://www.webtoolkit.info/
*
*
**/
sprintfWrapper = {
init : function () {
if (typeof arguments == "undefined") { return null; }
if (arguments.length < 1) { return null; }
if (typeof arguments[0] != "string") { return null; }
if (typeof RegExp == "undefined") { return null; }
var string = arguments[0];
var exp = new RegExp(/(%([%]|(\-)?(\+|\x20)?(0)?(\d+)?(\.(\d)?)?([bcdfosxX])))/g);
var matches = new Array();
var strings = new Array();
var convCount = 0;
var stringPosStart = 0;
var stringPosEnd = 0;
var matchPosEnd = 0;
var newString = '';
var match = null;
while (match = exp.exec(string)) {
if (match[9]) { convCount += 1; }
stringPosStart = matchPosEnd;
stringPosEnd = exp.lastIndex - match[0].length;
strings[strings.length] = string.substring(stringPosStart, stringPosEnd);
matchPosEnd = exp.lastIndex;
matches[matches.length] = {
match: match[0],
left: match[3] ? true : false,
sign: match[4] || '',
pad: match[5] || ' ',
min: match[6] || 0,
precision: match[8],
code: match[9] || '%',
negative: parseInt(arguments[convCount]) < 0 ? true : false,
argument: String(arguments[convCount])
};
}
strings[strings.length] = string.substring(matchPosEnd);
if (matches.length == 0) { return string; }
if ((arguments.length - 1) < convCount) { return null; }
var code = null;
var match = null;
var i = null;
for (i=0; i<matches.length; i++) {
if (matches[i].code == '%') { substitution = '%' }
else if (matches[i].code == 'b') {
matches[i].argument = String(Math.abs(parseInt(matches[i].argument)).toString(2));
substitution = sprintfWrapper.convert(matches[i], true);
}
else if (matches[i].code == 'c') {
matches[i].argument = String(String.fromCharCode(parseInt(Math.abs(parseInt(matches[i].argument)))));
substitution = sprintfWrapper.convert(matches[i], true);
}
else if (matches[i].code == 'd') {
matches[i].argument = String(Math.abs(parseInt(matches[i].argument)));
substitution = sprintfWrapper.convert(matches[i]);
}
else if (matches[i].code == 'f') {
matches[i].argument = String(Math.abs(parseFloat(matches[i].argument)).toFixed(matches[i].precision ? matches[i].precision : 6));
substitution = sprintfWrapper.convert(matches[i]);
}
else if (matches[i].code == 'o') {
matches[i].argument = String(Math.abs(parseInt(matches[i].argument)).toString(8));
substitution = sprintfWrapper.convert(matches[i]);
}
else if (matches[i].code == 's') {
matches[i].argument = matches[i].argument.substring(0, matches[i].precision ? matches[i].precision : matches[i].argument.length)
substitution = sprintfWrapper.convert(matches[i], true);
}
else if (matches[i].code == 'x') {
matches[i].argument = String(Math.abs(parseInt(matches[i].argument)).toString(16));
substitution = sprintfWrapper.convert(matches[i]);
}
else if (matches[i].code == 'X') {
matches[i].argument = String(Math.abs(parseInt(matches[i].argument)).toString(16));
substitution = sprintfWrapper.convert(matches[i]).toUpperCase();
}
else {
substitution = matches[i].match;
}
newString += strings[i];
newString += substitution;
}
newString += strings[i];
return newString;
},
convert : function(match, nosign){
if (nosign) {
match.sign = '';
} else {
match.sign = match.negative ? '-' : match.sign;
}
var l = match.min - match.argument.length + 1 - match.sign.length;
var pad = new Array(l < 0 ? 0 : l).join(match.pad);
if (!match.left) {
if (match.pad == "0" || nosign) {
return match.sign + pad + match.argument;
} else {
return pad + match.sign + match.argument;
}
} else {
if (match.pad == "0" || nosign) {
return match.sign + match.argument + pad.replace(/0/g, ' ');
} else {
return match.sign + match.argument + pad;
}
}
}
}
sprintf = sprintfWrapper.init;
