JS实现的生成随机数的4个函数分享

function NewGuid() {
    return (S4() + S4() + "-" + S4() + "-" + S4() + "-" + S4() + "-" + S4() + S4() + S4());
}

    function getBetweenRound(min,max){
        return Math.floor(min+Math.random()*(max-min));
    };

    function getCharCode(){
        for(var i=0,len=3;i<len;i++){
            var thisArr = charCodeIndex[i];
            for(var j=thisArr[0],thisLen=thisArr[1];j<=thisLen;j++){
                charCodeArr.push(j);
            }
        }
    }

    function ranStr(slen){
        slen = slen || 20;
        charCodeArr.length<62 && getCharCode();

        var res = [];
        for(var i=0;i<slen;i++){
            var index = getBetweenRound(0,61);
            res.push(String.fromCharCode(charCodeArr[index]));
        }
        return res.join('');
    };

    this.ranStr = ranStr;
})();