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javascript: get a function’s variable’s value within another function

Jack

javascript: get a function’s variable’s value within another function – Even if we have a good project plan and a logical concept, we will spend the majority of our time correcting errors abaout javascript and function. Furthermore, our application can run without obvious errors with JavaScript, we must use various ways to ensure that everything is operating properly. In general, there are two types of errors that you’ll encounter while doing something wrong in code: Syntax Errors and Logic Errors. To make bug fixing easier, every JavaScript error is captured with a full stack trace and the specific line of source code marked. To assist you in resolving the JavaScript error, look at the discuss below to fix problem about javascript: get a function’s variable’s value within another function.

Problem :

okay so I have this code in body:

<input type="text" value="haha" id="full_name"/>

And this code in script

<script language="javascript" type="text/javascript">
    function first(){
        var nameContent=document.getElementById('full_name').value;
    }

    function second() {
        first();
        y=nameContent; 
        alert(y);
    }
    second();
</script>

I want a alert showing the value of the element full_name, but it doesn’t seem to work, does anyone know why? :S

Solution :

nameContent only exists within the first() function, as you defined it within the first() function.

To make its scope broader, define it outside of the functions:

var nameContent;

function first(){
    nameContent=document.getElementById('full_name').value;
}

function second() {
    first();
    y=nameContent; alert(y);
}
second();

A slightly better approach would be to return the value, as global variables get messy very quickly:

function getFullName() {
  return document.getElementById('full_name').value;
}

function doStuff() {
  var name = getFullName();

  alert(name);
}

doStuff();

Your nameContent scope is only inside first function. You’ll never get it’s value that way.

var nameContent; // now it's global!
function first(){
    nameContent = document.getElementById('full_name').value;
}

function second() {
    first(); 
    y=nameContent; 
    alert(y);
}
second();

you need a return statement in your first function.

function first(){
    var nameContent = document.getElementById('full_name').value;
    return nameContent;
}

and then in your second function can be:

function second(){
    alert(first());
}

Your nameContent variable is inside the function scope and not visible outside that function so if you want to use the nameContent outside of the function then declare it global inside the <script> tag and use inside functions without the var keyword as follows

<script language="javascript" type="text/javascript">
    var nameContent; // In the global scope
    function first(){
        nameContent=document.getElementById('full_name').value;
    }

    function second() {
        first();
        y=nameContent; 
        alert(y);
    }
    second();
</script>

the OOP way to do this in ES5 is to make that variable into a property using the this keyword.

function first(){
    this.nameContent=document.getElementById('full_name').value;
}

function second() {
    y=new first();
    alert(y.nameContent);
}
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