title: Generate unique random alphanumeric using javascript
body: <p>code:</p>
  
  <pre><code>function alphanumeric()
  
  {
  
  var randomnum=Math.random().toString(36).substr(2,8);
  
  document.getElementbyId("textBoxId").value = randomnum;
  
  }
  </code></pre>
  
  <p>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,</p>
  
  <p>1.Is it only generate unique alphanumeric?</p>
  
  <p>2.How many alphanumeric this will generate?</p>
  
  <p>3.Is it possible to allow only unique alphanumeric?</p>
  
  <p>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...</p>