Passing javascript variable to controller?

Question

Yes, I know, this has already been answered, but I donot understand the answers or the methods.

I have a var of type STRING, say, myStr, I want to pass it to my controller method myMethod(). (it can also accept a string argument if needed).

CLARIFICATION : myMethod is a function in my CONTROLLER. JSCalltoController is the JS function that is called on clicking the button (THIS IS WITH ACTIONFUNCTION)

Sorry if there was any confusion.

What do I do?

Things I've tried :

1. Direct :

<button type="button" onclick="myMethod(myStr)">Enter</button>

The method is not called. I'm using system.debug to check whether the code reaches the function.

2. Actionfunction

<button type="button" onclick="JSCalltoController()">Enter</button>

<apex:actionFunction action="{!myMethod}" name="JSCalltoController">
    <apex:param name="myStr" assignTo="{!myStrController}" value="" />
</apex:actionFunction>

The above, ofcourse, fails.

If someone could demonstrate how to use this, It'd be nice.

There is a distinct lack of adequate (and in simple enough language) documentation/examples for many Visualforce elements.

**UPDATE : ** whole page is here : http://codepad.org/baQewaaA part of controller is here : http://codepad.org/fJsEu6TJ.

I am very frustrated right now, hours of searching and still no results. Anyone who can help me understand exactly WHAT is going wrong here, would win my lifelong gratitude.

Answer 1

You need to call your action function method from your button

<button type="button" onclick="JSCalltoController(myStr);">Enter</button>

and your action function will be same

<apex:actionFunction action="{!myMethod}" name="JSCalltoController">
    <apex:param name="myStr" assignTo="{!YOURCONTROLLERPROPERTY}" value="" />
</apex:actionFunction>

Apex Controller:

/*** Controller ***/
public class exampleCon {

public void setYOURCONTROLLERPROPERTY(String n) {
    YOURCONTROLLERPROPERTY = n;
}

public String getYOURCONTROLLERPROPERTY() {
    return YOURCONTROLLERPROPERTY;
}

public PageReference myMethod() {
    return null;
}

private String YOURCONTROLLERPROPERTY = 'no';
}