Evaluate and validate XPath/CSS selectors in Chrome Developer Tools
Method 1 : From Elements panel
Use the search function inside Elements panel to evaluate XPath/CSS selectors and highlight matching nodes in the DOM.
1.Press F12 to open up Chrome DevTools.
2.Elements panel should be opened by default.
3.Press Ctrl + F to enable DOM searching in the panel.
4.Type in XPath or CSS selectors to evaluate.
5.If there are matched elements, they will be highlighted in DOM. However, if there are matching strings inside DOM, they will be considered as valid results as well. For example, CSS selector header should match everything (inline CSS, scripts etc.) that contains the word header, instead of match only elements.
Method 2 : From Console panel
Execute tokens $x("some_xpath") or $$("css-selectors") in Console panel, which will both evaluate and validate.
1.Press F12 to open up Chrome DevTools.
2.Switch to Console panel.
3.Type in XPath like $x(".//header") to evaluate and validate.
4.Type in CSS selectors like $$("header") to evaluate and validate.
5.Check results returned from console execution
If elements are matched, they will be returned in a list. Otherwise an empty list [ ] is shown.
If the XPath or CSS selector is invalid, an exception will be shown in red text.
原文地址：https://www.cnblogs.com/MasterMonkInTemple/p/10558057.html