string concatenation in javascript

I have a javascript that checks for numeric values in a text box and I want to be able to apply it to all textboxes on the page.....here's my code and the id that is assigend to the checkboxes on the page.....what do i need to do differently?  

<SCRIPT LANGUAGE="Javascript">
<!--
var numcheck = /[^0-9]/;
function numVal(valthis)
{

      if(valthis.length < 1)
      {
            alert("Please enter a numeric value.")
            return false;
      }
      else
            {
                  if(numcheck.test(valthis))
                  {
                        alert("Please enter numbers only!")
        for (y=1;y<=16;y++){
                        picks.text + y + Value.focus();
                        picks.text + y + Value.select();
                                    }
                        return false;
                  }
                  return true;
            }

}

//-->
</SCRIPT>

<input name="text1Value" type="text" id="text1Value" size="2" maxlength="2" onBlur="numVal this.value)" />
<input name="text2Value" type="text" id="text2Value" size="2" maxlength="2" onBlur="numVal this.value)" />
<input name="text3Value" type="text" id="text3Value" size="2" maxlength="2" onBlur="numVal this.value)" />
<input name="text4Value" type="text" id="text4Value" size="2" maxlength="2" onBlur="numVal this.value)" />

This gives the alert okay but it loses focus and does not return to the "problem" textbox.  It works fine when applied to just one textbox and the textbox id is hardcoded into the javascript.  I think I am doing something wrong with the for statement and the string concatenation........