Is it possible to update a url link based on user text input?

Question

For instance, I know that it is possible to do something in Javascript that allows users to update text based on user text input:

<script type="text/javascript">
function changeText2(){
var userInput = document.getElementById('userInput').value;
document.getElementById('boldStuff2').innerHTML = userInput;
}
</script>
<p>Welcome to the site <b id='boldStuff2'>dude</b> </p> 
<input type='text' id='userInput' value='Enter Text Here' />
<input type='button' onclick='changeText2()' value='Change Text'/>

View the above code in action at: tizag.com/javascriptT/javascript-innerHTML.php

However, instead of the above code, I would like to know if it's possible to do something similar for a url link. Below I've placed a step by step example of what I would like to happen upon the user inputing text:

1. Original Link: http://www.google.com/search?q=

2. User Input in Text Field: espn

3. User clicks button to submit text in text field

4. Final Link: http://www.google.com/search?q=espn

Thanks for your help...BTW...if you can't tell I'm a bit of a novice so detail is appreciated.

Answer 1

Here's one in plain JS that updates as you type:

<a id="reflectedlink" href="http://www.google.com/search">http://www.google.com/search</a>
<input id="searchterm"/>

<script type="text/javascript">
    var link= document.getElementById('reflectedlink');
    var input= document.getElementById('searchterm');
    input.onchange=input.onkeyup= function() {
        link.search= '?q='+encodeURIComponent(input.value);
        link.firstChild.data= link.href;
    };
</script>

Note:

• no inline event handler attributes (they are best avoided);

• assigning both keyup and change, to try to get keyboard updates as they happen and ensure that all other updates get caught eventually;

• the use of encodeURIComponent(), necessary in case the search term has any non-ASCII or URL-special characters in;

• setting the search property of a Location (link) object to avoid having to write out the whole URL again;

• setting the data of the Text node inside the link to reflect the full URL afterwards. Don't set innerHTML from user input as it may have HTML-special characters like & and < in.

Answer 2

#1: you need some forms
#2: you need to catch when the form is submitted
#3: based on the form's submission change the url

Here is a demo: http://jsfiddle.net/maniator/K3D2v/show/
here is the code: http://jsfiddle.net/maniator/K3D2v/embedded/

HTML:

<form id="theForm">
    <input id='subj'/>
    <input type='submit'/>
</form>

JS:

var theForm = document.getElementById('theForm');
var theInput = document.getElementById('subj');

theForm.onsubmit = function(e){
    location = "http://jsfiddle.net/maniator/K3D2v/show/#" 
                              + encodeURIComponent(theInput.value);
    return false;
}