Replace in the input the string "script" with "code"... that way it will be output as "text". something like this maybe...
$('.edit').editable({
params: function(params) {
    var data = {};
    data['id']          = params.pk;
    data[params.name]   = params.value;
    return data;
},
success: function(response, newValue){
    //gi: Perform a global, case-insensitive replacement:
    newValue = newValue.replace(/script/gi, "code");
    $(".test").html(newValue); 
    //if newValue will be <script>alert('hello')</scipt>
    // then we see alert message with 'hello'
}
});
