<SCRIPT type="text/javascript" LANGUAGE="JavaScript"><!--
 function outputMoney(number) {
      number=checkval(number);
     return "$"+outputDollars(Math.floor(number-0) + '') + outputCents(number - 0);
 }

 function checkval(mycheckval) {
    mycheckval=mycheckval.replace(/,/g,"");
        mycheckval=mycheckval.replace(/\$/g,"");
        return (mycheckval);
 }

 function outputDollars(number) {
    if (number.length <= 3)
        return (number == '' ? '0' : number);
    else {
        var mod = number.length%3;
        var output = (mod == 0 ? '' : (number.substring(0,mod)));
        for (i=0 ; i < Math.floor(number.length/3) ; i++) {
            if ((mod ==0) && (i ==0))
                output+= number.substring(mod+3*i,mod+3*i+3);
            else
                output+= ',' + number.substring(mod+3*i,mod+3*i+3);
        }
        return (output);
    }
 } 

 function outputCents(amount) {
    amount = Math.round( ( (amount) - Math.floor(amount) ) *100);
    return (amount < 10 ? '.0' + amount : '.' + amount);
 }

 //--></SCRIPT>

 <input type="text" name="salary" onclick="this.value=checkval(this.value);this.select();" onBlur="this.value=outputMoney(this.value)"> 

 <form onsubmit="salary.value=checkval(salary.value)">