Disable executing JavaScript of a WebView

To disable JavaScript, set javaScriptEnabled property of WebPreferences, which was the property a WebView, to NO.

For example,

self.view.preferences.javaScriptEnabled = NO;

Reference: WebPreferences Class Reference - developer.apple.com

Now, if you edit WebView in a .xib file, you can also disable it by clearing a checkbox named "Enable JavaScript".
Otherwise, when you make a WebView in a source code, the property will be YES by default.