比较数据相同但标记不同的两个 HTML 页面的最佳方法是什么？

在本文中，我们将学习比较具有相同数据但不同标记的两个 HTML 页面的最佳方法。首先，我们需要知道如何比较两个 HTML 页面。现在，检查两个页面的最有效方法是使用两个页面内容的哈希码并比较它们是否相等。

JavaScript hashCode()：为了在 JavaScript 中实现 hashCode()，我们需要创建一个函数来生成散列代码。

现在，哈希码一般由以下实现构成。

s[0]*31^(n-1) + s[1]*31^(n-2) + ... + s[n-1]

哈希函数的JavaScript 代码：

Javascript

// Generate a hash code or string
    Object.defineProperty(String.prototype, 'hashCode', {
         value: function()
         {
           var hashValue = 0;
           var i, code;
           for (i = 0; i < this.length; i++)
           {
             // Returns the unicode of first character
             code  = this.charCodeAt(i);
             hashValue  = ((hashValue << 5) - hashValue) + code;
             hashValue |= 0;
           }
           return hashValue;
         }
    });

包含(hashValue << 5)的行与 ( hashValue * 31 + char) 相同。所以(hashValue <<5)是hashValue * 32而((hashValue << 5)-hashValue)是hashValue *31。以这种格式编写它只会使其更快并提高效率。

生成函数，我们需要提取两个页面的内容并生成以下哈希码。如果两者匹配，则两者相同，否则它们不同。结果通过使用 JavaScript 的innerHTML()函数的警报消息显示。

HTML代码：

HTML

  
    
    
       GeeksforGeeks 
      is a computer science portal that contains articles on mordern
      technologies as well as programming.It also helps us to prepare for
      various competitive programming competitions as well. So,that's why,
      GeeksforGeeks is recommended for every student out there who is eager to
      learn about new things related to mordern technology.
    
    
    
    
      
      GeeksforGeeks
      is a computer science portal that contains articles on mordern
        technologies as well as programming.It also helps us to prepare for
        various competitive programming competitions as well. So,that's why,
        GeeksforGeeks is recommended for every
        student out there who is eager to learn about new things related to
        mordern technology.
    
    
    
    
    
      // Generate a hash code or string
      Object.defineProperty(String.prototype, "hashCode", {
        value: function () {
          var hashValue = 0;
          var i, code;
 
          for (i = 0; i < this.length; i++) {
            // Returns the unicode of first character
            code = this.charCodeAt(i);
            hashValue = hashValue * 32 - hashValue + code;
 
            hashValue |= 0;
          }
          return hashValue;
        },
      });
      var hashValue1 = document.getElementById("pageID1").innerText.hashCode();
      var hashValue2 = document.getElementById("pageID2").innerText.hashCode();
 
      if (hashValue1 !== hashValue2) {
        document.getElementById("compareResultID").innerHTML =
          "They are different Pages";
      } else {
        document.getElementById("compareResultID").innerHTML = "Same Pages";
      }
    
  

输出：

如果内容不同，则将显示不同的输出。在第二个示例中，使用了更快的方法。

示例 2：

HTML

  
    
    
       GeeksforGeeks 
      is a computer science portal that contains articles on mordern
      technologies as well as programming.It also helps us to prepare for
      various competitive programming competitions as well. So,that's why,
      GeeksforGeeks is recommended for every student out there who is eager to
      learn about new things related to mordern technology.
    
    
    
    
      
      GeeksforGeeks
    
    
    
    
    
      // Generate a hash code or string
      Object.defineProperty(String.prototype, "hashCode", {
        value: function () {
          var hashValue = 0;
          var i, code;
          for (i = 0; i < this.length; i++) {
            // Returns the unicode of first character
            code = this.charCodeAt(i);
            hashValue = (hashValue << 5) - hashValue + code;
            hashValue |= 0;
          }
          return hashValue;
        },
      });
      var hashValue1 = document.getElementById("pageID1").innerText.hashCode();
      var hashValue2 = document.getElementById("pageID2").innerText.hashCode();
 
      if (hashValue1 !== hashValue2) {
        document.getElementById("compareResultID").innerHTML =
          "Different Pages";
      } else {
        document.getElementById("compareResultID").innerHTML =
          "They are same Pages";
      }
    
  

输出：