SOURCE

try{
 var result = ["a", "b"].indexOf("a");
 document.getElementById('indexof').innerHTML = result;
}catch(err){
 document.getElementById('indexof').innerHTML = '不支持';
}

try{
 var value = localStorage.setItem('key', 'value');
 document.getElementById('set').innerHTML = value;
}catch(err){
 document.getElementById('set').innerHTML = '不支持';
}

try{
 var value = localStorage.getItem('key');
 document.getElementById('get').innerHTML = value;
}catch(err){
 document.getElementById('get').innerHTML = '不支持';
}

<div>indexof</div>
<div id="indexof"></div>

<div>localStorage.set</div>
<div id="set"></div>

<div>localStorage.get</div>
<div id="get"></div>