update checkbox selected in javascript func in iOS

Question

I want to update the selected value of checkbox for javascript function in iOS. This is the HTML code for checkbox:

<input type='checkbox' name='displayraw' value='yes' selected='true' >

I want to change the selected= "false" or "true" when checkbox is checked or unchecked.

And here is my code: I used the webview to run submit function but cannot successful. I can change the value for textbox but cannot change the selected value for check box. Please help me. Thanks in advance.

NSString* temp = [self.webView stringByEvaluatingJavaScriptFromString:
                      [NSString stringWithFormat:
                       @"document.getElementsByName('%@')[0].selected='%@'",elementName, value]];

Answer 1

Checkboxes in HTML are checked NOT selected .

So if you simply change your code to something like this:
(notice how I have changed "selected" to "checked" in both examples):

Example HTML:

  <input type='checkbox' name='displayraw' value='yes' checked='checked' />

Example Objective-C:

NSString* temp = [self.webView stringByEvaluatingJavaScriptFromString:
                      [NSString stringWithFormat:
                       @"document.getElementsByName('%@')[0].checked='%@'",elementName, value]];

So if you make sure that your javascript string in Objective-C is being evaluated like this:

// use this
document.getElementsByName('displayraw')[0].checked = true;

Then it should check your checkbox.

UPDATE ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

To uncheck an 'checked' checkbox use:

document.getElementsByName('displayraw')[0].checked = false;

To check an 'unchecked' checkbox, use:

document.getElementsByName('displayraw')[0].checked = true;

SEE THIS JAVASCRIPT IN ACTION VIA JSFIDDLE HERE

Hope this helps!