How to convert a pixel value to a number value using JavaScript ?

The task is to convert the string value containing ‘px’ to the Integer Value with the help of JavaScript. Here, Few approaches are discussed.
Approach 1:

  • Use parseInt() method which takes string as first argument and return the Integer value.

Example 1: This example uses approach as discussed above

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<!DOCTYPE HTML>
<html>
  
<head>
    <title>
        Convert a pixel value to a number value using JavaScript.
    </title>
</head>
  
<body style="text-align:center;">
    <h1 style="color:green;">  
        GeeksForGeeks 
    </h1>
    <p id="GFG_UP" style="font-size: 19px; font-weight: bold;">
    </p>
    <button onclick="GFG_Fun()">
        click here
    </button>
    <p id="GFG_DOWN" 
       style="color: green;
              font-size: 24px; 
              font-weight: bold;">
    </p>
    <script>
        var el_up = document.getElementById("GFG_UP");
        var el_down = document.getElementById("GFG_DOWN");
        var n = el_up.style.fontSize;
        el_up.innerHTML = 
          "Click on the button to get the number value "+
          "from pixel value.<br>Pixel Value - '" + n + "'";
  
        function GFG_Fun() {
            el_down.innerHTML = "Integer value is " + parseInt(n, 10);
        }
    </script>
</body>
  
</html>

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Output:


    

  • Before clicking on the button:
    


    • 

  • After clicking on the button:
    


    • 



Approach 2:


    

  • Use RegExp  which replaces the ‘px’ by empty string and then convert the result to Integer using Number().
    • 



Example 2: This example uses approach as discussed above.











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<!DOCTYPE HTML> 


<html> 


  


<head> 


    <title> 


        Convert a pixel value to a number value using JavaScript. 


    </title> 


</head> 


  


<body style="text-align:center;"> 


    <h1 style="color:green;">   


        GeeksForGeeks  


    </h1> 


    <p id="GFG_UP" style="font-size: 19px; font-weight: bold;"> 


    </p> 


    <button onclick="GFG_Fun()"> 


        click here 


    </button> 


    <p id="GFG_DOWN" 


       style="color: green;  


              font-size: 24px;  


              font-weight: bold;"> 


    </p> 


    <script> 


        var el_up = document.getElementById("GFG_UP"); 


        var el_down = document.getElementById("GFG_DOWN"); 


        var n = el_up.style.fontSize; 


        el_up.innerHTML = "Click on the button to get the "+ 


          "number value from pixel value.<br>Pixel Value - '" + n + "'"; 


  


        function GFG_Fun() { 


            el_down.innerHTML =  


              "Integer value is " + Number(n.replace(/px$/, '')); 


        } 


    </script> 


</body> 


  


</html> 



















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Output:


    

  • Before clicking on the button:
    


    • 

  • After clicking on the button:
    


    • 



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