两个或多个id之间的多重关系？

i have minimum of two select box in html form to insert through POST but user can add more select boxes.Now i have to show relations between each n every inserted id.

like we have inserted 1,2,3,4 id..so i want it inserted in a table in two column as

(1-2) (1-3) (1-4) (2-3) (2-4) (3-4)

plzz reply to this and tell some idea about this any help??

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Simply iterate your array and make couples of next elements in same array:

function calculate() {
  var nums = document.getElementById('nums');

  nums = nums
    .value
    .split(',')
    .sort(function(a, b) {
      return parseInt(a) - parseInt(b);
    });

  for (var i = 0; i < nums.length; i++) {
    for (var j = i + 1; j < nums.length; j++) {
      console.log('(' + nums[i] + ' - ' + nums[j] + ')');
    }
  }
}
<input type="text" placeholder="1,2,5,8" id="nums" />
<button onClick="calculate()">Calculate</button>

</div>