Changing a links text

i have this javascript function that hides and shows content but i want to alternate the text link to say show and hide onclick here is the function below and it hides and shows on click but it dosent change the links description

if(this.document.getElementById( id).style.display=='none'){
this.document.getElementById( id).style.display='inline';

Set_Cookie('showRightCol','true',30,'/','','');
var show = Get_Cookie('showRightCol');
document['HideHandle'].write('<a href="#">Hide</a>');
}else{
this.document.getElementById( id).style.display='none';

Set_Cookie('showRightCol','false',30,'/','','');
var show = Get_Cookie('showRightCol');
document['HideHandle'].write('<a href="#">Show</a>');

}
}


this is where i use it
echo '<div onclick='hideRightCol("rightCol");'> <a href="#" id="HideHandle" name="HideHandle" alt="Expand or collapse menu">Hide </a></div>';