old_contents: /*
      Author: YeHong Du
      CreateAt: 2018-1-3
  */
  
  (function() {
      /* String */
      if (!String.prototype.trim) {
          String.prototype.trim = function () {
            return this.replace(/^[\s\uFEFF\xA0]+|[\s\uFEFF\xA0]+$/g, '');
          };
        }
  })();
new_contents: /*
      Author: YeHong Du
      CreateAt: 2018-1-3
  */
  
  (function() {
      /* String */
      if (!String.prototype.trim) {
          String.prototype.trim = function () {
            return this.replace(/^[\s\uFEFF\xA0]+|[\s\uFEFF\xA0]+$/g, '');
          };
      }
  	
  	// Production steps of ECMA-262, Edition 5, 15.4.4.14
  	// Reference: http://es5.github.io/#x15.4.4.14
  	if (!Array.prototype.indexOf) {
  	  Array.prototype.indexOf = function(searchElement, fromIndex) {
  	
  	    var k;
  	
  	    // 1. Let O be the result of calling ToObject passing
  	    //    the this value as the argument.
  	    if (this == null) {
  	      throw new TypeError('"this" is null or not defined');
  	    }
  	
  	    var O = Object(this);
  	
  	    // 2. Let lenValue be the result of calling the Get
  	    //    internal method of O with the argument "length".
  	    // 3. Let len be ToUint32(lenValue).
  	    var len = O.length >>> 0;
  	
  	    // 4. If len is 0, return -1.
  	    if (len === 0) {
  	      return -1;
  	    }
  	
  	    // 5. If argument fromIndex was passed let n be
  	    //    ToInteger(fromIndex); else let n be 0.
  	    var n = +fromIndex || 0;
  	
  	    if (Math.abs(n) === Infinity) {
  	      n = 0;
  	    }
  	
  	    // 6. If n >= len, return -1.
  	    if (n >= len) {
  	      return -1;
  	    }
  	
  	    // 7. If n >= 0, then Let k be n.
  	    // 8. Else, n<0, Let k be len - abs(n).
  	    //    If k is less than 0, then let k be 0.
  	    k = Math.max(n >= 0 ? n : len - Math.abs(n), 0);
  	
  	    // 9. Repeat, while k < len
  	    while (k < len) {
  	      // a. Let Pk be ToString(k).
  	      //   This is implicit for LHS operands of the in operator
  	      // b. Let kPresent be the result of calling the
  	      //    HasProperty internal method of O with argument Pk.
  	      //   This step can be combined with c
  	      // c. If kPresent is true, then
  	      //    i.  Let elementK be the result of calling the Get
  	      //        internal method of O with the argument ToString(k).
  	      //   ii.  Let same be the result of applying the
  	      //        Strict Equality Comparison Algorithm to
  	      //        searchElement and elementK.
  	      //  iii.  If same is true, return k.
  	      if (k in O && O[k] === searchElement) {
  	        return k;
  	      }
  	      k++;
  	    }
  	    return -1;
  	  };
  	}
  })();
  
subject: add indexOf()