Get the value by Document ID

Can anyone let me know what issue is there in the below code.
Basically, whatever I write in the text box, “Hello Manu” should get changed.
Is this possible?

We can write this in Jquery. But I wanted to see if we can execute it without Jquery

<h1>Change the HTML content</h1>
<h2 id=”hcontent”>Hello Manu</h2>
<input id=’x’ type=”text” value = searchURL()></input>
<script>
function searchURL() {
document.getElementById(“hcontent”).innerHTML=x
}
</script>