code:

function alphanumeric()

{

var randomnum=Math.random().toString(36).substr(2,8);

document.getElementbyId("textBoxId").value = randomnum;

}

Each time when I call alphanumeric() function this will generate alphanumeric random string and show on the Text Box like.. v3ta4t8l,zshqoc2u,9pey71rb...which works fine.. In my requirement I need to allow only unique alphanumeric. Could you please help me to solve my below question,

1.Is it only generate unique alphanumeric?

2.How many alphanumeric this will generate?

3.Is it possible to allow only unique alphanumeric?

4.It is possible to store unique alphanumeric in database use of primary key in my case already one of my column having primary key and so I will try to implement with the use of java script...

code:

function alphanumeric()

{

var randomnum=Math.random().toString(36).substr(2,8);

document.getElementbyId("textBoxId").value = randomnum;

}

Each time when I call alphanumeric() function this will generate alphanumeric random string and show on the Text Box like.. v3ta4t8l,zshqoc2u,9pey71rb...which works fine.. In my requirement I need to allow only unique alphanumeric. Could you please help me to solve my below question,

1.Is it only generate unique alphanumeric?

2.How many alphanumeric this will generate?

3.Is it possible to allow only unique alphanumeric?

4.It is possible to store unique alphanumeric in database use of primary key in my case already one of my column having primary key and so I will try to implement with the use of java script...

• javascript
• random

• Have you ever heard of GUIDs? – Matt Ball Commented May 22, 2014 at 5:14
• sorry..I do not have enough idea about that... – vicky Commented May 22, 2014 at 5:29
• I have looked at the answers and your question and I'm not sure what exactly you mean by unique. Do you want no repeated characters within one string or do you want to emit a series of unique strings when you call alphanumeric() repeatedly? – M Oehm Commented May 22, 2014 at 5:29
• I don't need to show any repeated same value...sorry for the inconvenient.. – vicky Commented May 22, 2014 at 5:42
• Related: how to generate uuid in javascript – Ja͢ck Commented May 22, 2014 at 5:48

2 Answers 2

Here's something that would return only unique alphanumerics

function alphanumeric_unique() {
    return Math.random().toString(36).split('').filter( function(value, index, self) { 
        return self.indexOf(value) === index;
    }).join('').substr(2,8);
}

FIDDLE

Splitting the string into an array of characters, then using Array.filter() to filter out any characters that are already in the array to get only one instance of each character, and then finally joining the characters back to a string, and running substr(2, 8) to get the same length string as in the question, where it starts at the second character and gets a total of eight characters.

 function IDGenerate() {
        var text = "";
        var hdntxt = "";
        var captchatext = "";
        var possible = "ABCDEFGHIkLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
        for (var i = 0; i < 7; i++) {
            text += possible.charAt(Math.floor(Math.random() * possible.length));         
        }

        document.getElementById("txtboxID").value = text;
        return false;
    }