Question

So I wrote this code so that every time someone clicks the submit button, a javascript
function, called check, will see if the text area is empty. If it is not, then the form will be submitted.
This is my code. Why isn’t it working?

<form method=post name='form_post' id='form_post' action='SUBMITIT.PHP'>
<textarea   id=message name=message class=post onfocus=this.className='post_focus';                                      
placeholder='Share your thoughts'  maxlength=500></textarea>
<br>
<button onclick='check()' id=button name=button>Post</button>
</form>


<script type="text/javascript"> 
function check() 
{ 
if(!document.textArea.message.value=="") 
{ 
document.forms["form_post"].submit();
}
} 
</script>

Thanks!

EDIT: I finally got it to work. Here’s a template if you are having a similar problem.

<!--The form-->
<form action="mypage.php" method="post" name="myForm" id="myForm">
<textarea name=myTextArea id=myTextArea>
</textarea>
</form>
<br>
<button onclick='check()'>
Post
</button>

<!--The script that checks-->
<script type="text/javascript"> 
function check(){ 
String.prototype.trim = function() { return this.replace(/^\s+|\s+$/g, ""); }; 
var textAreaValue=document.getElementById('myTextArea').value; 
var trimmedTextAreaValue=textAreaValue.trim(); 
if(trimmedTextAreaValue!="") { 
document.forms["myForm"].submit(); 
} 
} 
</script>

Answer 1

The following woks, and it also wipes unnecessary spaces, the form will only submit when given a character

<form action="yourpage.php" method="post" onsubmit="return check(this)">
    <textarea id="message"></textarea>
    <input type="submit" value="Post" />
</form>
<script>
function check(form){
    if (form.message.value.trim() == ""){
        return false
    }
}
</script>

This is the most simple way to do this, and the advised one.