Javascript boolean.toString()用法及代碼示例

boolean.toString()是javascript中的內置函數，用於根據指定的布爾對象的值返回“true”或“false”字符串。
用法:

boolean.toString()

參數：此函數不接受任何單個參數。
返回值：它根據指定的布爾對象的值返回“true”或“false”字符串。

讓我們看一下此boolean.toString()函數上的一些JavaScript代碼：

• 示例1:

  <script> 
  // Here Boolean object obj is  
  // created for the value true. 
  var obj = new Boolean(true); 
    
  // Here boolean.toString() function 
  // is used for the created object obj. 
  document.write(obj.toString()); 
  </script>

  輸出：

  true

• 示例2:

  <script> 
  // Here Boolean object obj is  
  // created for the value 1. 
  var obj = new Boolean(1); 
    
  // Here boolean.toString() function is 
  // used for the created object obj. 
  document.write(obj.toString()); 
  </script>

  輸出：

  true

• 示例3:

  <script> 
  // Here Boolean object obj is 
  // created for the value -1. 
  var obj = new Boolean(-1); 
    
  // Here boolean.toString() function is 
  // used for the created object obj. 
  document.write(obj.toString()); 
  </script>

  輸出：

  true

• 示例4:

  <script> 
  // Here Boolean object obj is 
  // created for the value 1.2 
  var obj = new Boolean(1.2); 
    
  // Here boolean.toString() function is 
  // used for the created object obj. 
  document.write(obj.toString()); 
  </script>

  輸出：

  true

• 示例5:

  <script> 
  // Here Boolean object obj is created  
  // for the value as string "gfg" 
  var obj = new Boolean("gfg"); 
    
  // Here boolean.toString() function is  
  // used for the created object obj. 
  document.write(obj.toString()); 
  </script>

  輸出：

  true

• 示例6:

  <script> 
  // Here Boolean object obj is created 
  // for the value false. 
  var obj = new Boolean(false); 
    
  // Here boolean.toString() function is 
  // used for the created object obj. 
  document.write(obj.toString()); 
  </script>

  輸出：

  false

錯誤和異常：

• 示例1:這裏的值geeksforgeeks會給出錯誤，因為不僅未定義該值，而且還預定義了false。

  <script> 
  // Here Boolean object obj is created  
  // for the value geeksforgeeks. 
  var obj = new Boolean(geeksforgeeks); 
    
  // Here boolean.toString() function is 
  // used for the created object obj. 
  console.log(obj.toString()); 
  </script>

  輸出：

  Error: geeksforgeeks is not defined

• 示例2:在這裏，不能將複數作為參數，而隻能將整數值和字符串作為參數，這就是它返回錯誤的原因。

  <script> 
  // Here Boolean object obj is created for the 
  // value such as complex number 1+2i 
  var obj = new Boolean(1 + 2i); 
    
  // Here boolean.toString() function is  
  // used for the created object obj. 
  console.log(obj.toString()); 
  </script>

  輸出：

  Error: Invalid or unexpected token

應用：

• 此函數的應用程序將根據給定對象的值返回“true”或“false”字符串。
  讓我們看看此應用程序上的JavaScript程序：
  例：

  <script> 
  // Here Boolean object obj  
  // is created for the value 27 
  var obj = new Boolean(27); 
    
  // Here boolean.toString() function is  
  // used for the created object obj. 
  document.write(obj.toString()); 
  </script>

  輸出：

  true