How to check a selector matches some content using jQuery?

In order to know whether the jQuery selector selected any element or not, Here 2 methods are discussed and these are mostly used methods.

Example-1: In this example, Selector searches for <p> element. This example uses the length property to check If something is selected or not. In this case <p> element is found.

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<!DOCTYPE html>
<html>
  
<head>
    <title>
        JQuery | 
      check if a selector matches something.
    </title>
    <script src=
"https://ajax.googleapis.com/ajax/libs/jquery/3.4.0/jquery.min.js">
  </script>
</head>
  
<body style="text-align:center;" id="body">
    <h1 style="color:green;">  
            GeeksForGeeks  
        </h1>
    <p>
        A computer science portal for geeks.
    </p>
    <button onclick="gfg_Run()">
        check
    </button>
    <p id="GFG_DOWN" 
       style="color:green; 
              font-size: 20px;">
    </p>
    <script>
        var el_down = 
            document.getElementById("GFG_DOWN");
        var str = '';
  
        function gfg_Run() {
            if ($("p").length) {
                str = "Something Selected";
            } else {
                str = "Nothing Selected";
            }
            el_down.innerHTML = str;
        }
    </script>
</body>
  
</html>

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Output:


    

  • 
Before clicking on the button:
    


    • 

  • 
After clicking on the button:
    


    • 



Example-2: In this example, Selector searches for <a> element. This example also uses the length  property to check, If something is selected or not. In this case <a> element is not found. 











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<!DOCTYPE html> 


<html> 


  


<head> 


    <title> 


        JQuery |  


      check if a selector matches something. 


    </title> 


    <script src= 


"https://ajax.googleapis.com/ajax/libs/jquery/3.4.0/jquery.min.js"> 


  </script> 


</head> 


  


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


    <h1 style="color:green;">   


            GeeksForGeeks   


        </h1> 


    <p> 


        A computer science portal for geeks. 


    </p> 


    <button onclick="gfg_Run()"> 


        check 


    </button> 


    <p id="GFG_DOWN" 


       style="color:green; 


              font-size: 20px;"> 


    </p> 


    <script> 


        var el_down =  


            document.getElementById("GFG_DOWN"); 


        var str = ''; 


  


        function gfg_Run() { 


            if ($("a").length) { 


                str = "Something Selected"; 


            } else { 


                str = "Nothing Selected"; 


            } 


            el_down.innerHTML = str; 


        } 


    </script> 


</body> 


  


</html> 



















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Output:


    

  • 
Before clicking on the button:
    


    • 

  • 
After clicking on the button:
    


    • 



Example-3: In this example, Selector searches for <button> element. This example uses the exists  function to check, If something is selected or not. In this case <button> element is found. 











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                                    code
                                




















<!DOCTYPE html> 


<html> 


  


<head> 


    <title> 


        JQuery |  


      check if a selector matches something. 


    </title> 


    <script src= 


"https://ajax.googleapis.com/ajax/libs/jquery/3.4.0/jquery.min.js"> 


  </script> 


</head> 


  


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


    <h1 style="color:green;">   


            GeeksForGeeks   


        </h1> 


    <p> 


        A computer science portal for geeks. 


    </p> 


    <button onclick="gfg_Run()"> 


        check 


    </button> 


    <p id="GFG_DOWN" 


       style="color:green;  


              font-size: 20px;"> 


    </p> 


    <script> 


        var el_down =  


            document.getElementById("GFG_DOWN"); 


        var str = ''; 


        jQuery.fn.exists = function() { 


            return this.length > 0; 


        } 


  


        function gfg_Run() { 


            if ($("button").exists()) { 


                str = "Something Selected"; 


            } else { 


                str = "Nothing Selected"; 


            } 


            el_down.innerHTML = str; 


        } 


    </script> 


</body> 


  


</html> 



















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Output:


    

  • 
Before clicking on the button:
    


    • 

  • 
After clicking on the button:
    


    • 






    

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