How to replace lowercase letters with an other character in JavaScript ?

Given a string and the task is to replace all lowercase letters from a string with the other characters. The method which are used to replace the character are described below:

  • replace() method: This method searches a string for a defined value, or a regular expression, and returns a new string with the replaced defined value.

    Syntax:



    string.replace(searchVal, newvalue)

    Parameters:

    • searchVal: It is required parameter. It specifies the value, or regular expression, that is going to replace by the new value.
    • newvalue: It is required parameter. It specifies the value to be replaced the search value.

    Return value: It returns a new string where the defines value has been replaced by the new value.

Example 1: This example replaces the lowercase letters with . (dot) using replace() method.

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<!DOCTYPE HTML> 
<html
    <head
        <title
            Replace lowercase letters with an other characters
        </title>
    </head
      
    <body style = "text-align:center;"
          
        <h1 style = "color:green;"
            GeeksForGeeks 
        </h1
          
        <p id = "GFG_UP" style = "font-size: 16px; font-weight: bold;">
        </p>
          
        <button onclick = "gfg_Run()"
            Click here
        </button>
          
        <p id = "GFG_DOWN" style
            "color:green; font-size: 20px; font-weight: bold;">
        </p>
          
        <script>
            var el_up = document.getElementById("GFG_UP");
            var el_down = document.getElementById("GFG_DOWN");
            var str = "THISiISgGEEKSFORGEEKS!";
            el_up.innerHTML = str;
              
            function gfg_Run() {
                el_down.innerHTML = str.replace(/[a-z]/g, ".");
            }         
        </script
    </body
</html>                    

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Output:

  • Before clicking on the button:
  • After clicking on the button:

Example 2: This example replaces the lowercase letters with (‘ ‘)(space) by going to the each character and checking if it is lowercase, If it is then replacing occurs.

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<!DOCTYPE HTML> 
<html
    <head
        <title
            Replace lowercase letters with an other character
        </title>
    </head
      
    <body style = "text-align:center;"
      
        <h1 style = "color:green;"
            GeeksForGeeks 
        </h1
          
        <p id = "GFG_UP" style = "font-size: 16px; font-weight: bold;">
        </p>
          
        <button onclick = "gfg_Run()"
            Click here
        </button>
          
        <p id = "GFG_DOWN" style
            "color:green; font-size: 20px; font-weight: bold;">
        </p>
          
        <script>
            var el_up = document.getElementById("GFG_UP");
            var el_down = document.getElementById("GFG_DOWN");
            var str = "THISiISgGEEKSFORGEEKS!";
            el_up.innerHTML = str;
              
            function gfg_Run() {
                var newStr = "";
                  
                for(var i=0; i<str.length; i++) { 
                    if (str.charCodeAt(i) >= 97 && 
                            str.charCodeAt(i) <= 122) {
                        newStr += ' ';
                    }
                    else {
                        newStr += str[i];
                    }
                }
                el_down.innerHTML = newStr;
            }         
        </script
    </body
</html>                    

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Output:

  • Before clicking on the button:
  • After clicking on the button:


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