How to check if string contains only digits in JavaScript ?

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.

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<!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>                    

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Output:


    

  • 
Before clicking on the button:
    


    • 

  • 
After clicking on the button:
    


    • 



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











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<!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>                     



















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Output:


    

  • 
Before clicking on the button:
    


    • 

  • 
After clicking on the button:
    


    • 



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