I'm trying to execute some JS before the page's onLoad event fires.
But I'm having trouble successfully calling stringByEvaluatingJavaScriptFromString in the webViewDidStartLoad delegate method.
To reproduce the issue, you can use the following code.
Delegate implementation:
-(void)webViewDidStartLoad:(UIWebView *)webView {
[webView stringByEvaluatingJavaScriptFromString:@"window.valueHasBeenSet=true"];
}
View this HTML:
<html>
<head></head>
<body>
<script type="text/javascript" charset="utf-8">
if (window.valueHasBeenSet)
{
// We enter this branch the first time
document.write('<h3>Everything is OK. Value has been set.</h3>');
}
else
{
// We incorrectly enter this branch on reloads
document.write('<h3>Error. Value has not been set.</h3>');
}
</script>
<a href="javascript:window.location.reload()">Reload</a>
</body>
</html>
This page works on the first view ("Everything is OK.") but fails on all reloads, regardless of the reload method. As you'd probably expect, this doesn't work in the shouldStartLoadWithRequest delegate, either.
I also tried executing the javascript immediately following webViewDidStartLoad with performSelector:withObject:afterDelay:0, to no avail.
Any ideas?