Client Side Web Development

Re: Call JavaScript function based on (string) variable value - how?

BlackCatBone — Wed, 09 Jul 2008 13:32:29 GMT

This is my solution. The code fragment shows how the eval function was used to form a function call. The code checks for the existence of the js function before calling it. It also passes two string parameter values.

targetPageScript = the name of the JavaScript in the external library

parm1 = the value of the 1st string parameter

parm2 = the value of the 2nd string parameter

            if (eval('typeof(' + targetPageScript + ')') == 'function')
            {
                eval(targetPageScript + '("' + parm1  + '", "' + parm2 + '");');
            }
            else
            {
   	        alert('JavaScript function "' + targetPageScript + '" could not be found.  No attempt was made to call the function.');
            }

Re: Call JavaScript function based on (string) variable value - how?

BlackCatBone — Wed, 09 Jul 2008 12:39:51 GMT

Thanks for the replies. I agree that I did not explain my situation well. I'll try to do better. Here goes:

We have external libraries of JavaScript functions. We have an aspx page (page "A") that contains a generalized JavaScript function that calls another JavaScript in one our several external JavaScript libraries. Here's the twist: The name of the JavaScript function to be called is passed as a string variable to the JavaScript function on page "A". I don't know how to generate a valid function call to an external library starting with a variable that holds the function name.

This is a simplified version on the JavaScript on page "A".

function CallExternal(functionName)
{
// here I need to call the function named in the functionName parameter. functionName is a string.
}

I need to replace the comment in the function with the correct syntax.

Thanks!

Re: Call JavaScript function based on (string) variable value - how?

bubblesnout — Tue, 08 Jul 2008 23:14:03 GMT

Try and explain your situation a little better. Probably with an examle of the code you are using. If you need to reference a function in an external library, always put your Javascript library references first; before your own javascript. That way you can be sure that the functions are accessible. If you for some reason can't do this, usually you can just add the function to your window.onload. eg.

window.onload = function(){
A();
};

Re: Call JavaScript function based on (string) variable value - how?

AceCorban — Tue, 08 Jul 2008 22:15:08 GMT

//--------other library
function B()
{
    //do stuff
}
//--------end other library

function A()
{
     //do stuff
     B();
}

The only reason I can forsee why you might get an error is if the other library isn't loaded first. Function A will complain that it can't find Function B if it is declared after function A is called.

Call JavaScript function named in a string variable - how?

BlackCatBone — Tue, 08 Jul 2008 21:26:39 GMT

Greetings,

I need to call JavaScript function "B" based on a string value passed to JavaScript function "A". JavaScript function "B" resides in an external library and is not present on the page where function "A" exists. What is the syntax to do this?

Thanks,

BCB