Dave's Brain

Browse - programming tips - javascript does a file exist

Date: 2009jun23
Language: javaScript

Q.  How can I find out of a file exists using javaScript?

A.  Do Ajax with the HEAD command like this:

// Helper
function getAjax() {
	return (!window.XMLHttpRequest)? (new ActiveXObject('Microsoft.XMLHTTP')):(new XMLHttpRequest());
}

function isExists(url) {
	var req;
	
	req = getAjax();
	try {
		req.open('HEAD', url, false); // We block (ie wait for the return)
		req.send(null);
	}
	catch(e) {
		return false;	// for IE6
	}
	
	return req.status == 200;
}

function exampleUse() {
	var	i;

	for (i = 1; i < 10000; i++) {
		padded = zeroPad(i, 5);
		if (!isExists('http://www.example.com/photos/DSC'+padded+'.JPG')) break;
	}

	alert('There are '+i-1+' photos');
}

Add a comment

Sign in to add a comment