Submit the search text field with out submit

How I suppose to write the code for text box to submit the search with out search button?

Please suggest I have pasted the code below.

I need only text box with out search button, when I enter some thing in textbox and press enter that will take automatically.

please help me.....

$form['basic']['inline']['keys'] = array(
'#type' => 'textfield',
'#title' => '',
'#default_value' => $keys,
'#size' => 30,
'#maxlength' => 255,

'#attributes' => array('class' => 'ms-sbplain', 'onClick' => 'if(this.value == "Search")this.value=""'),

);

$form['basic']['inline']['submit'] = array('#type' => 'submit', '#value' => 'Search', '#title' => t('Search'));