CODEWITHSUNDEEP
javascript
Kaz Wolfe
Kaz Wolfe

Reputation: 438

How would one generate a MAC address in Javascript?

I need to generate a random MAC address for a project of mine, and I can not get it to work. Below is my current code (that is not working).

function genMAC(){
// Make a new array with all available HEX options.
var colours = new Array("0","1","2","3","4","5","6","7","8","9","A","B","C","D","E","F");
// Make variable to hold 6 character HEX array
partA = new Array(1);
partB = new Array(1);
partC = new Array(1);
partD = new Array(1);
partE = new Array(1);
partF = new Array(1);
mac-address="";
for (i=0;i<2;i++){
    // Loop for partA
    partA[i]=colours[Math.round(Math.random()*14)];
}
    for (i=0;i<2;i++){
    // Loop through 6 times, randomising the letter added to the array
    partB[i]=colours[Math.round(Math.random()*14)];
}
    for (i=0;i<2;i++){
    // Loop through 6 times, randomising the letter added to the array
    partC[i]=colours[Math.round(Math.random()*14)];
}
    for (i=0;i<2;i++){
    // Loop through 6 times, randomising the letter added to the array
    partD[i]=colours[Math.round(Math.random()*14)];
}
    for (i=0;i<2;i++){
    // Loop through 6 times, randomising the letter added to the array
    partE[i]=colours[Math.round(Math.random()*14)];
}
    for (i=0;i<2;i++){
    // Loop through 6 times, randomising the letter added to the array
    partF[i]=colours[Math.round(Math.random()*14)];
}
// Returns like "a10bc5". It is likely that you may need to add a "#".
mac-address = partA + ":" + partB + ":" + partC + ":" + partD + ":" + partE + ":" + partF;
return mac-address;

}

Ugly. I'm fairly new to JS and I am wondering if there is an easier way to do this that would work.

Upvotes: 14

Views: 10536

Answers (3)

Ashley Strout
Ashley Strout

Reputation: 6258

Here is a bit more of a "clean" version of your code, which takes the number of loops down to one. On each iteration of the loop, it appends two random characters to the macAddress variable, and if it's not the last iteration, it also appends a colon. Then it returns the generated address.

function genMAC(){
    var hexDigits = "0123456789ABCDEF";
    var macAddress = "";
    for (var i = 0; i < 6; i++) {
        macAddress+=hexDigits.charAt(Math.round(Math.random() * 15));
        macAddress+=hexDigits.charAt(Math.round(Math.random() * 15));
        if (i != 5) macAddress += ":";
    }

    return macAddress;
}

Aside from being more complicated than necessary, there were two problems with your code. The first was that mac-address is an invalid variable name due to the dash. That caused the code to not work at all. With that fixed, the other problem was that when setting the MAC address variable at the end, you appended arrays to a string. That caused each of the arrays containing two hex digits to be converted to a string, which meant a comma was put between the two digits.

Upvotes: 13

guest271314
guest271314

Reputation: 1

"XX:XX:XX:XX:XX:XX".replace(/X/g, function() {
  return "0123456789ABCDEF".charAt(Math.floor(Math.random() * 16))
});

jsfiddle http://jsfiddle.net/guest271314/qhbC9/

Upvotes: 46

Yaje
Yaje

Reputation: 2821

try this Jsfiddle

all i did was to fix the display part :

function genMAC(){
var colours = new Array("0","1","2","3","4","5","6","7","8","9","A","B","C","D","E","F");
// Make variable to hold 6 character HEX array
var partA = new Array(1);
var partB = new Array(1);
var partC = new Array(1);
var partD = new Array(1);
var partE = new Array(1);
var partF = new Array(1);
var mac_address="";
for (i=0;i<2;i++){

    // Loop for partA
    partA[i]=colours[Math.round(Math.random()*14)];
}
    for (i=0;i<2;i++){
    // Loop through 6 times, randomising the letter added to the array
    partB[i]=colours[Math.round(Math.random()*14)];
}
    for (i=0;i<2;i++){
    // Loop through 6 times, randomising the letter added to the array
    partC[i]=colours[Math.round(Math.random()*14)];
}
    for (i=0;i<2;i++){
    // Loop through 6 times, randomising the letter added to the array
    partD[i]=colours[Math.round(Math.random()*14)];
}
    for (i=0;i<2;i++){
    // Loop through 6 times, randomising the letter added to the array
    partE[i]=colours[Math.round(Math.random()*14)];
}
    for (i=0;i<2;i++){
    // Loop through 6 times, randomising the letter added to the array
    partF[i]=colours[Math.round(Math.random()*14)];
}
// Returns like "a10bc5". It is likely that you may need to add a "#".
mac_address = partA[0]+ partA[1] + ":" + partB[0]+ partB[1] + ":" + partC[0]+ partC[1] + ":" + partD[0] + partD[1] + ":" + partE[0] + partE[1] + ":" + partF[0] + partF[1];
alert(mac_address);
}

if you just print/alert the array for example partA it would display like 3,2 and not 32 so you need to concatenate it each index it has.

Upvotes: 1

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