How to check if a submit button has been clicked in javascript

Question

I am new to javascript language,and i couldnt find a javascript approach for this php statement:

if( isset($_POST['submit']) ){
//more if statements
} else { echo 'Error'; }

In other words,i want to make a form validation in javascript to check if a submit button has been pressed.

Answer 1

Use .onclick :

Demo on Fiddle

HTML:

<input type="submit" />

JavaScript:

var submit = document.getElementsByTagName('input')[0];
submit.onclick = function() {
    alert("Button pressed!");
}

Answer 2

In JavaScript you don't necessarily "check if the submit button has been pressed", you respond to the submit button's events. For example, the form has a submit event:

function someHandlerFunction() {
    // respond to the form submit event here
}

var form = document.getElementById('theFormId');
form.addEventListener("submit", someHandlerFunction);

Or you can respond to the click event of the button itself:

var button = document.getElementById('theButtonId');
button.addEventListener("click", someHandlerFunction);

Answer 3

You have to add an onclick event to the submit button. So when the button in the form is pressed, you run a function.
Basically it can look like this:

 function save(){ alert(document.getElementById("myInput").value); } 

 <input id="myInput" type="text" value="test"> <button onclick="save()">Save!</button>