How can I call different function

I have a form:

From Date: ... To Date: ... Vehicle Number: ... button (show record) dropdownmenu

I enter the dates (from and to) and vehicle number it select the record right when I click on button, but now I want to do it that when I select another opti开发者_如何学JAVAon from drop-down menu the form remains the same:

From Date: ... To Date: ... Vehicle Number: ... button (show record) drop-down menu

when I click the button it will take only from Date field value and run another query and ignore to data and vehicle number.

In short: on select option of drop-down menu I will change the onClick event of button to run another query.

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Not totally sure what your asking, but if you want a certain function to run on the selection of a select box option, why not use a onchange event on the select box?

<select id="mySelect" onchange="runFunction(document.getElementById('mySelect').value);">
    <option value="myValue"></option>
    <option value="moreValues"></option>
    <option value="anotherValue"></option>
</select>

then the function can do different things depending on the values it has been passed a simple example would be

function runFunction(option){
    if(option === "myValue"){
        Do something
    }
}