button to run a function code example
Example 1: how to call a function with a button in javascript
<script>
function myFunction()
{
document.write("<h1>HELLO</h1>")
}
</script>
<button onclick="myFunction()">Click</button>
Example 2: run a function when a button has the onclick
<script>
function myFunction() {
alert("ALERT THIS FUNCTION HAS RUNNED");
}
</script>
<button onclick="myFunction">click to run function</button>