function(needle) {
        if (arr.indexOf) {
          return arr.indexOf(needle);
        } else {
          for (var i=0, length=arr.length; i<length; i++) {
            if (arr[i] === needle) { return i; }
          }
          return -1;
        }
    }
function(needle) {
        if (arr.indexOf) {
          return arr.indexOf(needle);
        } else {
          for (var i=0, length=arr.length; i<length; i++) {
            if (arr[i] === needle) { return i; }
          }
          return -1;
        }
    }
function ( needle ) { if ( arr . indexOf ) { return arr . indexOf ( needle ) ; } else { for ( var i = 0 , length = arr . length ; i < length ; i ++ ) { if ( arr [ i ] === needle ) { return i ; } } return - 1 ; } }
Check whether a given object exists in an array and return index
If no elelemt found returns -1

@example
wysihtml5.lang.array([1, 2]).indexOf(2);
// => 1
Check whether a given object exists in an array and return index If no elelemt found returns - 1
Find the index of a given tag