Check if the browser supports document.querySelectorAll in JavaScript

问题

Now although most modern browser support document.querySelectorAll(), you may run into problems with older versions of Internet Explorer. The obvious way of checking if the browser supports a function would be:

if(document.querySelectorAll){
    //some random code
}

But from what I understand some browsers like (IE8) don't support certain properties, like 'body *'. Is there a better way to check if document.querySelectorAll('body *') will actually work?

回答1:

document.querySelectorAll will thrown on any unsupported selector so you can simply use a try-catch block.

回答2:

Test browser support or not , without try-catch :

function QuerySelectors() {
  return (document['querySelector']&&document['querySelectorAll'])!=null;
}

or

function QuerySelectors(){
  return typeof(document['querySelector'])=='function'&&typeof(document['querySelectorAll'])=='function';
}

Read more : Reference

回答3:

Use typeof to check it:

 if(typeof(document.querySelectorAll) != 'undefined'){
      //some random code
 }

来源：https://stackoverflow.com/questions/22286844/check-if-the-browser-supports-document-queryselectorall-in-javascript