How to check if string contains only digits in JavaScript ?

Last Updated : 29 May, 2019

Given a string and the task is to check whether it contains only digits or not.

JavaScript test() Method: This method tests for a pattern in a string. This method returns true if match is found, otherwise it returns false.

Syntax:

RegExpObject.test(str)

Parameters: This function accepts single parameter str which is required. It specifies the string which to be searched.

Example 1: This example checks for the non-digit string by using RegExp.

<!DOCTYPE HTML>  
<html>  
    <head>  
        <title>  
            Check if string contains only digits 
        </title> 
    </head>  
      
    <body style = "text-align:center;" id = "body">  
      
        <h1 style = "color:green;" >  
            GeeksForGeeks  
        </h1> 
      
        <p id = "GFG_UP" style = "font-size: 15px; font-weight: bold;"> 
        </p> 
          
        <button onclick = "gfg_Run()">  
            check 
        </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 path = "4323424242"; 
            el_up.innerHTML = "String = '"+path + "'"; 
          
            function gfg_Run() { 
                el_down.innerHTML = /^\d+$/.test(path); 
            }          
        </script>  
    </body>  
</html>                     

Output:

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

Example 2: This example checks for the non-digits string by using RegExp.

<!DOCTYPE HTML>  
<html>  
    <head>  
        <title>  
            Check if string contains only digits 
        </title> 
    </head>  
      
    <body style = "text-align:center;" id = "body">  
      
        <h1 style = "color:green;" >  
            GeeksForGeeks  
        </h1> 
      
        <p id = "GFG_UP" style = "font-size: 15px; font-weight: bold;"> 
        </p> 
          
        <button onclick = "gfg_Run()">  
            check 
        </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 path = "+4323424242"; 
            el_up.innerHTML = "String = '"+path + "'"; 
          
            function gfg_Run() { 
                el_down.innerHTML = !/\D/.test(path); 
            }          
        </script>  
    </body>  
</html>                     

Output:

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

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