Trying to get a name in a function

Hello, I am trying to get the element image_url name to the new_text() function
I dont know how I would do this I am a beginner at javascript.

<script language="JavaScript">
function new_text(field_value){
document.form.+field_value+.value="New Text";
}
</script>

<input name="image_url5" type="text" onclick="new_text(this.value)">
[/code]

The problem is that I have 30 textfields like this with all different names, so that is
why I am trying to use a function. Thanks

Why not trying something like :

<script language="JavaScript">
function getName(Field_value) {document.write('<script language="JavaScript">' +
'function newText() {document.form.' + field_value + '.value="NewText";}</script>');}</script>

And calling this two functions :
<input name="image_url5" type="text" onclick="getName(this.value); newText();">


It's a little bite barbarian but, let's try turning around this trick.

Of course, you have already tried :

<script language="JavaScript">
function newText() {document.form.this.value="NewText";}</script>

And :

<script language="JavaScript">
function newText() {Field = this.value;
document.form.Field.value="NewText";}</script>

Or just :

<input name="image_url5" type="text" onclick="this.value='New Text'">

Thank you, I got it working.