代码...
<!DOCTYPE html>
<html>
<head>
<script src="http://code.jquery.com/jquery-1.9.1.js"></script>
<script type="text/javascript">
$(document).ready(function() {
$("#add_variation").click(function(){
var tag_val = $("#materials_input").val();
// check if tag already added
$("#adding_area_result").each(function() {
if($(this).text() == tag_val){
alert("same value again");
return false;
}else{
// insert tags
$("#adding_area_result").add('<li><span rel="variation_area" class="variation1_tag">'+tag_val+'</span><input type="hidden" name="variation1[]" id="variation1" value="'+tag_val+'" /></li>').appendTo("#adding_area_result");
}
});
});
});
</script>
</head>
<body>
<br>
<input type="text" maxlength="2048" class="text" name="materials_input" id="materials_input" />
<br>
<br>
<input type="button" value="Add" class="button-medium" id="add_variation" />
<div id="adding_area_result">
</div>
</body>
</html>