Question

144

Multiply two values in a form

rated 0 times [ 145] [ 1] / answers: 1 / hits: 7814 / 11 Years ago, tue, december 3, 2013, 12:00:00

For my code, I am trying to call 2 parameters into a function. Once you have left the 2nd input box, and multiply the 2 numbers passed through and put it in the third text box. if either of the first 2 input boxes are empty, then color them light red. This is my code so far, what am I missing?

Javascript:

function multiply(one, two) {

if(one==){

this.style.color='red';

}

if(two==){

this.style.color='red';

}

else{

txt1=one * two;

return txt1;

}



}

HTML5:

First Value: <input type=text name=mFirst />

Second Value: <input type=text name=mLast onblur=multiply(mFirst.value, mLast.value) />

Multiplication of First and Second Value: <input type=text name=answer>

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iliana

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3 Years ago

answered 11 Years ago stacie · Accepted Answer

<input … onblur=multiply.call(this,this.form.elements.mFirst.value,this.form.elements.mLast.value) >

function multiply(one, two) {

  if(one && two){

    this.form.elements.answer.value = one * two;

  } else {

    this.style.color='red';

  }

}

Empty strings are non-truthy values, thus one && two will only be true if neither value is an empty string.

Using call allows you to set the value of this used inside the function.

Demo: http://jsfiddle.net/b5Ltt/

You might want to look at the HTML5 <output> element.