Run Javascript in UIWebView

gistfile1.m

// From: http://iphoneincubator.com/blog/windows-views/how-to-inject-javascript-functions-into-a-uiwebview
NSString *title = [webView stringByEvaluatingJavaScriptFromString:@"document.title"]; 

[webView stringByEvaluatingJavaScriptFromString:@"var script = document.createElement('script');"  
                         "script.type = 'text/javascript';"  
                         "script.text = \"function myFunction() { "  
                            "var field = document.getElementById('field_3');"  
                            "field.value='Calling function - OK';"  
                         "}\";"  
                         "document.getElementsByTagName('head')[0].appendChild(script);"];  
  
[webView stringByEvaluatingJavaScriptFromString:@"myFunction();"];