Javascript - input and character conversion

Question

I want to capture input characters in a text box, then convert according to the table and put them back into the text box as user types.

<form id='myForm'>

Enter phone number:<input type="text" id='idMyText' name="myText" onKeyUp="alphaToNum(this.value)">
</form>




<script>
// on each keypress in input box, I want to capture key pressed,
// determine if key pressed belong to group of identified characters
// if, so then convert to specified numeric equivalent and return character 
// to text box.
// This mapping corresponds to numeric characters on blackberry device.
// Normally user has to press alt+letter to get numbers. This will provide
// quicker access to numeric characters on for numeric fields

function alphaToNum(e) {
 x = e;
 x = (x.replace(/W/, "1"));
 x = (x.replace(/E/, "2"));
 x = (x.replace(/R/, "3"));
 x = (x.replace(/S/, "4"));
 x = (x.replace(/D/, "5"));
 x = (x.replace(/F/, "6"));
 x = (x.replace(/Z/, "7"));
 x = (x.replace(/X/, "8"));
 x = (x.replace(/C/, "9")); 
 document.getElementById('idMyText').value = x; 
}

</script> 

Answer 1

Gotta do the trick. Now it works wherever there are carriages, and even when you copy / paste WECZ into the field (if that matters)

var conversionMap = {W:1,E:2,R:3,S:4,D:5,F:6,Z:7,X:8,C:9};
function alphaToNum(){
    var field = document.getElementById('idMyText');
    var value = field.value.split('');
    var i = 0, len = value.length;

    for(i;i<len;i++){
        if (conversionMap[value[i]]) {
            value[i] = conversionMap[value[i]];
        }
    }
    field.value = value.join('');
    // prevent memory leak.
    field = null;
}

** Edit after comment by Tim Downs **

Answer 2

This might be better done when the value changes at the input, rather than when a key is pressed. Otherwise, other input forms (insertion value) bypass this replacement.

Answer 3

. , , / WECZ ( )

var conversionMap = {W:1,E:2,R:3,S:4,D:5,F:6,Z:7,X:8,C:9};
function alphaToNum(){
    var field = document.getElementById('idMyText');
    var value = field.value.split('');
    var i = 0, len = value.length;

    for(i;i<len;i++){
        if (conversionMap[value[i]]) {
            value[i] = conversionMap[value[i]];
        }
    }
    field.value = value.join('');
    // prevent memory leak.
    field = null;
}

its work is good until we used utf-8 characters like öéáí etc ... any idea to repair this "leak"?