Limit characters in a text box added with javascript

I am using the following link & script to add a value to a text box. Could someone help me limit this so it can only be run once or limit the text box to not allow more than 7 characaters? Maxlength on the text box doesn't work. If I click the link twice it will enter the value twice right next to eachother.

<a href="##" value="happy" onclick="addme(this.value)">Add it</a>

<script>
    function addme(iii) {
    var txt=document.getElementById("theTxtBox").value;
    txt=txt + iii;
    document.getElementById("theTxtBox").value=txt;
    }
</script>

Open in new window

earwig75Asked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Big MontySenior Web Developer / CEO of ExchangeTree.org Commented:
if you only want to run it once, or ALWAYS just add the links value, just comment out the line of code as shown below:

<a href="##" value="happy" onclick="addme(this.value)">Add it</a>

<script>
    function addme(iii) {
    //var txt=document.getElementById("theTxtBox").value;
    //txt=txt + iii;
    document.getElementById("theTxtBox").value=iii;
    }
</script>

Open in new window


however, if you want to just limit the input to a max of 7 characters, use the following code:

<a href="##" value="happy" onclick="addme(this.value)">Add it</a>

<script>
    function addme(iii) {
    var txt=document.getElementById("theTxtBox").value;
    txt=txt + iii;
    if( txt.length >= 7 )
         alert( 'Too many characters');
    else
        document.getElementById("theTxtBox").value=txt;
    }
</script>

Open in new window

0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
JavaScript

From novice to tech pro — start learning today.