Is there a php echo/print equivalent in javascript

You can use

function echo(content) {  
    var e = document.createElement("p");
    e.innerHTML = content;
    document.currentScript.parentElement.replaceChild(document.currentScript, e);
}

which will replace the currently executing script who called the echo function with the text in the content argument.

You need to use document.write()

<div>foo</div>
<script>
document.write('<div>Print this after the script tag</div>');
</script>
<div>bar</div>

Note that this will only work if you are in the process of writing the document. Once the document has been rendered, calling document.write() will clear the document and start writing a new one. Please refer to other answers provided to this question if this is your use case.

// usage: log('inside coolFunc',this,arguments);
// http://paulirish.com/2009/log-a-lightweight-wrapper-for-consolelog/
window.log = function(){
  log.history = log.history || [];   // store logs to an array for reference
  log.history.push(arguments);
  if(this.console){
    console.log( Array.prototype.slice.call(arguments) );
  }
};

Using window.log will allow you to perform the same action as console.log, but it checks if the browser you are using has the ability to use console.log first, so as not to error out for compatibility reasons (IE 6, etc.).

You can use document.write, however it's not a good practice, it may clear the entire page depends on when it's being executed.

You should use Element.innerHtml like this:

<div>foo</div>
<span id="insertHere"></span>
<div>bar</div>

<script>
document.getElementById('insertHere').innerHTML = '<div>Print this after the script tag</div>';
</script>