CODEWITHSUNDEEP
javascript
al3x609
al3x609

Reputation: 181

Why is my JavaScript function "a" not defined?

When I call my JavaScript function B, the JavaScript console in Firefox said that function A is not defined, but on Chrome browser it's defined. And when I call function "A" in body segment:

<input type="button" onclick="A()" value=" ..A.. ">

Firefox said that function B is not defined. Why? 

<html>
    <head>
        <script language="javascript" type="text/javascript">
            function B() {
                alert(" hi B ");
                document.write('<br><br><input type="button" onClick="A()" value=" ..A..">');
            };

            function A() {
                alert(" hi A");
                document.write('<br><br><input type="button" onclick="B()" value=" ..b..">');
                if (window.WebCL == undefined) {
                    alert("Unfortunately your system does not support WebCL. ");
                    return false;
                }
            }
        </script>
    </head>
    <body>
        <input type="button" onclick="B()" value=" ..B.. ">
    </body>
</html>

Upvotes: 5

Views: 5038

Answers (3)

Ehsan Khodarahmi
Ehsan Khodarahmi

Reputation: 4922

Try this one:

<html>
<head>
<script language="javascript" type="text/javascript">

var  A = function() {
   alert(" hi A");
   document.write('<br><br><input type="button" onclick="B()" value=" ..b..">');
   if (window.WebCL == undefined) {
     alert("Unfortunately your system does not support WebCL. ");
     return false;
   }
 }  

 function B(){
   alert(" hi B ");     
   document.body.innerHTML = ('<br><br><input type="button" onClick="new A()" value=" ..A..">'); 
 }

    </script>
    </head>

<body>
   <input type="button" onclick="B()" value=" ..B.. ">
</body>

</html>

Upvotes: 2

Cheran Shunmugavel
Cheran Shunmugavel

Reputation: 8459

The problem is that you are calling document.write after the page has loaded, which effectively wipes out the existing content of the page, including the embedded script. You should be using DOM manipulation methods instead.

Upvotes: 3

stefan bachert
stefan bachert

Reputation: 9626

The first write clears the content of the document, resulting in function A being undefined

Upvotes: 4

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