[Yo!]

In my application (yes I know that it's asp) I need to automatically replace a character if it is found in the textbox
Is there a way to do this.
If it helps this is how it renders on the page

<textarea id="ContentPlaceHolder1_TextBox3" cols="20" rows="2" name="ctl00$ContentPlaceHolder1$TextBox3"/>

Is there a way to call a function when the textbox's text is changed. I want to replace ("!") with (".").
Thanks in advance!
-Yo!

EDIT
if it helps here is the vb equivalent:

    Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged
        TextBox1.Text = TextBox1.Text.Replace("!", ".")
    End Sub

This post has been edited by Yo!: 12 November 2011 - 07:46 PM

[Dormilich]

I’d try

document.getElementById("ContentPlaceHolder1_TextBox3").addEventListener("input", function () {
    this.value = this.value.replace("!", ".");
}, true);

… in a decently modern browser

This post has been edited by Dormilich: 12 November 2011 - 08:10 PM

[Atli]

For compatibility with older browsers, you can use the change event instead. The simples way would be to:

• Create function you want executed when the content changes:
  

  function onTextBoxChange( box ) {
      // This replaces all "!" with "."
      box.value = box.value.replace(/!/g, ".");
  }
  
  

  
  
  
• Set the "onchange" property on the textarea in question to execute this function:
  

  <textarea onchange="onTextBoxChange(this)" ... />
  
  

This way; setting the "onchange" property on the element, rather than setting the event in Javascript, is the surest way to support older browsers. What Dormilich suggested, for example, would fail in all versions of Internet Explorer except 9 and later, as they don't support addEventListener. (Which is one great reason for using libraries like jQuery. They take care of all that while still allowing you to avoid putting Javascript into the HTML like this.)

Another issue is that this only executes once the input loses focus, not right away. You could set the keypress event as well to instantly swap out characters when typing into a box.

function onTextBoxKeyPress(box, evt) {
	if ( evt.charCode == 33 ) {
		evt.preventDefault();
		box.value += ".";
	}
}

<textarea onkeypress="onTextBoxKeyPress(this, event)" ... />

[Dormilich]

the IE equivalent (IE before version 9) to the input event would be

var area = document.getElementById("ContentPlaceHolder1_TextBox3");
area.attachEvent('onpropertychange', function() {
    area.value = area.value.replace("!", ".");
});

[Yo!]

Thank you very much for all of your help!
You guys are life savers.
Yo!