How to use the DOM locators in Selenium

I've the HTML source like this,

<input type="image" onclick="return logSub();" src="/images/Login_submit.gif" width="105" height="33" border="0" />

Here there is no ID or NAME. So I can only locate this using image index (which is hard) or using the src tag? But I dont know how use the src tag?

Is that possible开发者_如何学编程?

See my answer to a previous question here: selenium: Is it possible to use the regexp in selenium locators

Basically the dom= protocol allows you to use javascript to locate elements for Selenium.

or with css:

css=input[type=image], [src="/images/Login_submit.gif"]

Have you tried

//input[@src='/images/Login_submit.gif']

Try this locator:

//input[contains(@src, 'Login_submit.gif')].