addField() Demo
Code
JavaScript Code
//Add more fields dynamically.
function addField(field,area,limit) {
if(!document.getElementById) return; //Prevent older browsers from getting any further.
var field_area = document.getElementById(area);
var all_inputs = field_area.getElementsByTagName("input"); //Get all the input fields in the given area.
//Find the count of the last element of the list. It will be in the format '<field><number>'. If the
// field given in the argument is 'friend_' the last id will be 'friend_4'.
var last_item = all_inputs.length - 1;
var last = all_inputs[last_item].id;
var count = Number(last.split("_")[1]) + 1;
//If the maximum number of elements have been reached, exit the function.
// If the given limit is lower than 0, infinite number of fields can be created.
if(count > limit && limit > 0) return;
if(document.createElement) { //W3C Dom method.
var li = document.createElement("li");
var input = document.createElement("input");
input.id = field+count;
input.name = field+count;
input.type = "text"; //Type of field - can be any valid input type like text,file,checkbox etc.
li.appendChild(input);
field_area.appendChild(li);
} else { //Older Method
field_area.innerHTML += "<li><input name='"+(field+count)+"' id='"+(field+count)+"' type='text' /></li>";
}
}
HTML Code
<form name="frm" method="POST">
<strong>Friends List</strong><br />
<ol id="friends_area">
<li><input type="text" name="friend_1" id="friend_1" /></li>
<li><input type="text" name="friend_2" id="friend_2" /></li>
<li><input type="text" name="friend_3" id="friend_3" /></li>
<li><input type="text" name="friend_4" id="friend_4" /></li>
<li><input type="text" name="friend_5" id="friend_5" /></li>
</ol>
<input type="button" value="Add Friend Field" onclick="addField('friends_area','friend_',10);" />
<strong>Enemies List</strong><br />
<ol id="enemies_area">
<li><input type="text" name="enemy_1" id="enemy_1" /></li>
<li><input type="text" name="enemy_2" id="enemy_2" /></li>
<li><input type="text" name="enemy_3" id="enemy_3" /></li>
<li><input type="text" name="enemy_4" id="enemy_4" /></li>
<li><input type="text" name="enemy_5" id="enemy_5" /></li>
</ol>
<input type="button" value="Add Friend Field" onclick="addField('enemies_area','enemy_',0);" />
</form>
