Javascript「if and else」語句

Question

我有一個Terms of Service頁面，我想強制用戶在點擊接受按鈕之前檢查Checkbox。否則，它應該顯示彈出消息說

請繼續

之前閱讀服務條款，如果它檢查並接受按鈕，他們將重定向到官方網站。

任何人都可以幫助我嗎？

Answer 1

試試這個：

<SCRIPT> 

//Accept terms & conditions script (by InsightEye www.insighteye.com) 
//Visit JavaScript Kit (http://javascriptkit.com) for this script & more. 

function checkCheckBox(f) { 
    if (f.agree.checked == false) { 
    alert('Please check the box to continue.'); 
    return false; 
    } else { 
    return true; 
    } 
} 
</SCRIPT> 

<form action="/yourscript.cgi-or-your-page.html" method="GET" 
onsubmit="return checkCheckBox(this)"> 

    <!--Enter your form contents here--> 
    <b>By submitting, I agree that all info entered was done 
    accurately & truthfully.</b><br> 
    I accept: <input type="checkbox" value="0" name="agree"> 
    <input type="submit" value="Submit form"> 
    <input type="button" value="Exit" onclick="document.location.href='/index.html';"> 
</form> 

或本：

<form name="frm"> 
    <input type="checkbox" name="chk" onClick="apply()">If you click this the specified 
    url will open. 
    <div align=center>&copy<a href="http://www.mine.com" style="color:#3D366F;text-decoration:none;cursor:pointer;font-size=13px">hscripts.com</a></div> 
</form> 
<script type="text/javascript"> 
    function apply() { 
    if(document.frm.chk.checked==true) { 
    window.open("http://www.mine.com/license/license.html"); 
    } 
    } 
</script> 

Answer 2

入住這condition在submit handler。

if (formname.checkboxname.checked == true) 
    { 
     //showalert 

     return false; 
    }else{ 

    //open your page 
    }