How to call JavaScript function from html - Stack Overflow

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How we can call start() JavaScript function for this case from HTML:

(function() {
  var never, start;
  
  never = function() {
   return alert("try");
 }; 

  start = function() {
   return alert("try harder");
 };


}).call(this);

My HTML

<input type="button" value="press" onclick="never()" ></input>

How we can call start() JavaScript function for this case from HTML:

(function() {
  var never, start;
  
  never = function() {
   return alert("try");
 }; 

  start = function() {
   return alert("try harder");
 };


}).call(this);

My HTML

<input type="button" value="press" onclick="never()" ></input>

• javascript
• html
• jquery

Share Improve this question Follow edited Aug 6, 2022 at 17:22 Brian Tompsett - 汤莱恩 5,8937272 gold badges6161 silver badges133133 bronze badges asked Dec 4, 2012 at 14:44 Mohit VermaMohit Verma 1,66022 gold badges2121 silver badges3131 bronze badges 2

• You should consider converting the script you provided to a class. – povilasp Commented Dec 4, 2012 at 14:48
• Exactly like this, but never is not the global and therefore cannot be found. – Felix Kling Commented Dec 4, 2012 at 14:48

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3 Answers 3

Sorted by: Reset to default 4

When you assign event handler code to attributes, any functions that are used need to be available in the global variable scope.

To acplish this, you can make them properties of window. Currently, your never and start functions are local to the IIFE function scope.

   // IIFE function
(function() {

  //  var never, start;  // local variables

     // Make the functions globally scoped
   window.never = function() {
      return alert("try");
   }; 

   window.start = function() {
      return alert("try harder");
   };
}).call(this);

---

You can expose a single namespace if you prefer

   // IIFE function
(function() {

   var ns = window.ns = {};

     // Make the functions globally scoped
   ns.never = function() {
      return alert("try");
   }; 

   ns.start = function() {
      return alert("try harder");
   };
}).call(this);

And then change your inline handler to use ns.never(); and ns.start();.

First give your input tag an id:

<input id="someInputField" type="button" ... />

Next register a callback on it by executing code when the document is ready:

$(document).ready( function() {
    // define a function called never
    function never() {
        alert( 'Never say never');
    }

    // register a function on the click event handler of that input tag:
    $('#someInputField').click( never );
});

You may find it easier to use a javascript library like jQuery. Using that library you can do this:

<script type="text/javascript">
    $(document).ready(function() {
        var count = 0
        $("#tryme").click(function () {
            if (count == 0) {
                alert('try');
                count++
            }
            else if (count == 1) {
                alert('try harder');
            }
        });
    });
</script>

<input type="button" value="press" id="tryme" ></input>

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