function	applyEvent()
{
	var text = document.getElementById("test");
	alert(text.innerHTML);
}


function upload_image(id)
{
	if (!id)
		id = 'uploadfilebox';
	var el = $(id);
	var form = document.createElement("form");
	form.name = "myform";
	form.method = "post";
	form.action = "javascript:alert(this.firstChild.innerHTML)";
	
	var input = document.createElement("input");
	input.name = "image";
	input.type = "file";
	input.id = "test";
	
	var submit = document.createElement("input");
	submit.type = "submit"
	submit.value = "Envoyer";
	
	
	form.appendChild(input);
	form.appendChild(submit);
	
	form.action = "javascript:applyEvent()";
	
	el.appendChild(form);
}

<a tabindex="-1" href="javascript:void(0);" onclick="surroundText(\'<code>\', \'</code>\', \''.$textareaId.'\'); return false;">
			<img src="'.$baseurl.'plugins/dokuwiki/img/source.png" align="bottom" alt="Insert Code" title="Insert Code" border="0" /></a>
			<a tabindex="-1" href="javascript:void(0);" onclick="surroundText(\'<code php>\', \'