MaskingText for ASP.NET

// JScript File

function ReplaceString(mask)
{
    var rstring="";
    var maskR=mask.replace(/[\#|\@|\?]/g,'');
    var maskC=maskR.split('');
    for (var i=0;i<maskC.length;i++)
    {
        if (i!=maskC.length-1){rstring += "\\" + maskC[i] + "|";}
        else {rstring += "\\" + maskC[i];}
    }
    return rstring;
}
function processText(id,mask)
{
    
    if (mask==""){return;}
    this.mask=mask;
    this.id=id;
    this.pos=doGetCaretPosition(id);
    var pos=doGetCaretPosition(id);
    var text=document.getElementById(id).value;
    var rstring=ReplaceString(mask);
    var myRegExp = '/' + rstring + '/g';
    this.formattedText=text.replace(eval(myRegExp),'');
    document.getElementById(id).value=applyFormat(formattedText,mask);
    setCursorToNextLiteralChar();
}

function setCursorToNextLiteralChar()
{
    var currChar=this.mask.charAt(this.pos);
    var ipos=this.pos;
    while (isMaskingChar(currChar))
    {
        ipos++;
        currChar=this.mask.charAt(ipos);
    }
    setCaretPosition(this.id,ipos);
}

function isMaskingChar(character)
{
    var mask=this.mask;
    var maskR=mask.replace(/[\#|\@|\?]/g,'');
    var maskC=maskR.split('');
    var isMC=false;
    for (var i=0;i<maskC.length;i++)
    {
        if (character==maskC[i])
        {
            isMC=true;
            break;
        }
    }
    return isMC;
}
function applyFormat(text,format)
{
    for(var i=text.length;i<mask.length;i++)
    {
        text+="_";
    }
    var toReturn="";
    var gc=0;
    for(var j=0;j<format.length;j++)
    {
        if ((format.substring(j,j+1)!="#") && (format.substring(j,j+1)!="?") && (format.substring(j,j+1)!="@"))
        {
            toReturn+=format.substring(j,j+1);
        }
        else
        {
            toReturn+=text.substring(gc,gc+1);
            gc++;
        }
    }
    return toReturn;
}





//Code Got from internet regarding setting and getting the position of a cursor in text box
function doGetCaretPosition (ctrl) {
    var CaretPos = 0;
    // IE Support
    if (document.selection) {
	    document.getElementById(ctrl).focus();
	    var Sel = document.selection.createRange();
	    Sel.moveStart ('character', -document.getElementById(ctrl).value.length);
	    CaretPos = Sel.text.length;
    }
    // Firefox support
    else if (ctrl.selectionStart || ctrl.selectionStart == '0')
	    CaretPos = ctrl.selectionStart;
	//alert("FUN");    
    return (CaretPos);
}

function setCaretPosition(ctrl, pos)
{
    if(document.getElementById(ctrl).setSelectionRange)
    {
	    document.getElementById(ctrl).focus();
	    document.getElementById(ctrl).setSelectionRange(pos,pos);
    }
    else if (document.getElementById(ctrl).createTextRange) {
	    var range = document.getElementById(ctrl).createTextRange();
	    range.collapse(true);
	    range.moveEnd('character', pos);
	    range.moveStart('character', pos);
	    range.select();
    }
}

function checkKey(id,mask)
{
    //alert(event.keyCode);
    if ((event.keyCode!=8)&&(event.keyCode!=46)&&(event.keyCode!=37)&&(event.keyCode!=38)&&(event.keyCode!=39)&&(event.keyCode!=40))
    {
        if (mask==""){return;}
        this.id=id;
        this.pos=doGetCaretPosition(id);
        this.mask=mask;
        var currChar=this.mask.charAt(this.pos);
        if (currChar=="#")
        {
            if (!Digit()){return false;}
        }
        else if (currChar=="@")
        {
            if (!Alpha()){return false;}
        }
        else if (currChar=="?")
        {
            return true;
        }
        else 
        {
            return true;
        }
    }
    else
    {
        return true;
    }
}

function Digit()
{
    if (((event.keyCode >=96) && (event.keyCode <=105)) || ((event.keyCode >=48) && (event.keyCode <=57)) ){return true;}else{return false;}
}

function Alpha()
{
    if ((event.keyCode >=65) && (event.keyCode <=90)){return true;}else{return false;}
}