下面是一个很好用的Replace javascript function.

function replaceSubstring(inputString, fromString, toString)
{
    var temp = inputString;
    if (fromString == "")
    {
        return inputString;
    }
    if (toString.indexOf(fromString) == -1) {
    while (temp.indexOf(fromString) != -1) {
        var toTheLeft = temp.substring(0, temp.indexOf(fromString));
        var toTheRight = temp.substring(temp.indexOf(fromString)+fromString.length, temp.length);
        temp = toTheLeft + toString + toTheRight;
    }
    } else {
        var midStrings = new Array("~", "`", "_", "^", "#");
    var midStringLen = 1;
    var midString = "";
    while (midString == "") {
    for (var i=0; i < midStrings.length; i++) {
    var tempMidString = "";
    for (var j=0; j < midStringLen; j++) { tempMidString += midStrings; }
    if (fromString.indexOf(tempMidString) == -1) {
    midString = tempMidString;
    i = midStrings.length + 1;
    }
    }
    }
    while (temp.indexOf(fromString) != -1) {
    var toTheLeft = temp.substring(0, temp.indexOf(fromString));
    var toTheRight = temp.substring(temp.indexOf(fromString)+fromString.length, temp.length);
    temp = toTheLeft + midString + toTheRight;
    }
    while (temp.indexOf(midString) != -1) {
    var toTheLeft = temp.substring(0, temp.indexOf(midString));
    var toTheRight = temp.substring(temp.indexOf(midString)+midString.length, temp.length);
    temp = toTheLeft + toString + toTheRight;
    }
    }
    return temp;
}