Passing Arrays to JavaScript Web Resources as parameter

Despite the availability of Business Rules, JavaScript is still an important way to customize Dynamics CRM UI, especially in complex scenarios (or when you just need to hide a section).

If you ever need to pass an Array as parameter inside the Event Handler form, you can declare it with the square brackets or using the Array keyword:

// square brackets
[1, 2, 3, 4 ,5]
// Array keyword
new Array(1, 2, 3, 4, 5)

CRM Event Handler:


As example we write a function to hide fields passing their logicalname as an array:

["name", "accountnumber", "telephone1"]

the function handles the parameter in this way:

function HideFields(fields) {
    for (var count = 0; count fields.length; count++) {
        if (Xrm.Page.getControl(fields[count]) != null) {
            Xrm.Page.getControl(fields[count]).setVisible(false);
        }
    }
}

If a parameter is an Array, multiple parameters can still be passed inside the Event Handler. For example:

// note the comma before the array is declared
true, ["name", "accountnumber", "telephone1"]

In this way we are sending a boolean as first parameter to our updated function:

function ShowHideFields(isVisible, fields) {
    for (var count = 0; count fields.length; count++) {
        if (Xrm.Page.getControl(fields[count]) != null) {
            Xrm.Page.getControl(fields[count]).setVisible(isVisible);
        }
    }
}

There is another way to pass multiple parameters without declaring each parameter inside the function definition and without using an Array: the arguments variable.
In JavaScript the arguments variable holds automatically all the parameters passed to a function.
We can rewrite the previous example, inside the Event Handler we pass the values as separate parameters, not as an array:

// no square brackets, no Array Keywords, just 3 separate parameters
"name", "accountnumber", "telephone1"

and our function is simply this one:

function HideFields() {
    for (var count = 0; count arguments.length; count++) {
        if (Xrm.Page.getControl(arguments[count]) != null) {
            Xrm.Page.getControl(arguments[count]).setVisible(false);
        }
    }
}

But if we want to handle a specific element (like the first element) we need to take care inside the code:

// we decided that the first parameter will contain the value for the isVisible variable
true, "name", "accountnumber", "telephone1"

function ShowHideFields() {
    // this function requires at least 2 parameters
    if (arguments.length > 1) {
        var isVisible = arguments[0];
        // we start the for cycle from 1 instead of 0
        for (var count = 1; count arguments.length; count++) {
            if (Xrm.Page.getControl(arguments[count]) != null) {
                Xrm.Page.getControl(arguments[count]).setVisible(isVisible);
            }
        }
    }
}