javascript自动生成包含数字与字符的随机字符串

2019-11-20 13:11:50

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本文实例讲述了javascript自动生成包含数字与字符的随机字符串的方法。分享给大家供大家参考。具体如下：

这里主要用到Math.random() 和 Math.floor() 两个函数

Math.random() -- 返回0和1之间的伪随机数可能为0，但总是小于1，[0,1)

Math.floor() -- 向下取整，舍掉小数字后的值

实现随机多位数的方法：

复制代码代码如下:

/** 
* 
*    随机生成数字 
* 
*@param num 生成数字位数 
*/  
function randomNumber(num){  
        return ''+Math.floor(Math.random() * num) ;  
}

javascript 随机生成字符

以下实例为随机 A-Z / a-z区间中随机出现的字符

复制代码代码如下:

/** 
 *
 *    随机生成 
 *
 *@param data json数据 例：{"start":0,"end":2,"number":5,"upper":true}  
 *@param start  开始下标 
 *@param end    结束下标 
 *@param number 生成位数 
 *@param upper  是否大写 默认为小写 
 */  
function randomLetter(data){  
    var letterData = "";  
    var lowercase = new Array("a","b","c","d","e","f","g","h","i","g","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z");  
  
    var uppercase = new Array("A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z");  
    var start = data.start;  
    var end = data.end;  
    var number = data.number;  
    var upper = data.upper;  
  
    var length = end - start;  
    for(var i= 0;i < number; i++){  
        var index = Math.floor(Math.random() * length) + start;  
        var letter = "";  
        if(upper){  
            letter = uppercase[index];  
        }else{  
            letter = lowercase[index];  
        }  
        letterData += letter;  
    }  
    return letterData;   
}